Sorry for late reply. Finally I have some time off work. Here is dump of my settings:
/interface bridge
add admin-mac=xxx auto-mac=no comment=defconf name=bridge
/interface wifi
set [ find default-name=wifi1 ] channel.band=5ghz-ax .skip-dfs-channels=\
10min-cac .width=20/40/80mhz configuration.country=Czech .mode=ap .ssid=\
Gateway-Wireless-5GHz disabled=no security.authentication-types=\
wpa2-psk,wpa3-psk .ft=yes .ft-over-ds=yes
set [ find default-name=wifi2 ] channel.band=2ghz-ax .skip-dfs-channels=\
10min-cac .width=20/40mhz configuration.country=Czech .mode=ap .ssid=\
Gateway-Wireless disabled=no security.authentication-types=\
wpa2-psk,wpa3-psk .ft=yes .ft-over-ds=yes
/interface vlan
add interface=ether1 name=vlan-848 vlan-id=848
/interface pppoe-client
add add-default-route=yes disabled=no interface=vlan-848 max-mru=1492 \
max-mtu=1492 name=pppoe-client1 user=cetin
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/ip pool
add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server
add address-pool=default-dhcp interface=bridge name=defconf
/disk settings
set auto-media-interface=bridge auto-media-sharing=yes auto-smb-sharing=yes
/interface bridge port
add bridge=bridge comment=defconf interface=ether2
add bridge=bridge comment=defconf interface=ether3
add bridge=bridge comment=defconf interface=ether4
add bridge=bridge comment=defconf interface=ether5
add bridge=bridge comment=defconf interface=wifi1
add bridge=bridge comment=defconf interface=wifi2
/ip neighbor discovery-settings
set discover-interface-list=LAN
/interface list member
add comment=defconf interface=bridge list=LAN
add comment=defconf interface=ether1 list=WAN
/interface ovpn-server server
add mac-address=xx name=ovpn-server1
/ip address
add address=192.168.88.1/24 comment=defconf interface=bridge network=\
192.168.88.0
/ip dhcp-client
add comment=defconf interface=ether1
/ip dhcp-server network
add address=192.168.88.0/24 comment=defconf dns-server=192.168.88.1 gateway=\
192.168.88.1
/ip dns
set allow-remote-requests=yes servers=1.1.1.1,1.0.0.1
/ip dns static
add address=192.168.88.1 comment=defconf name=router.lan type=A
/ip firewall filter
add action=accept chain=input comment=\
"defconf: accept established,related,untracked" connection-state=\
established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
invalid
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=accept chain=input comment=\
"defconf: accept to local loopback (for CAPsMAN)" dst-address=127.0.0.1
add action=drop chain=input comment="defconf: drop all not coming from LAN" \
in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy" \
ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy" \
ipsec-policy=out,ipsec
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" \
connection-state=established,related hw-offload=yes
add action=accept chain=forward comment=\
"defconf: accept established,related, untracked" connection-state=\
established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
connection-state=invalid
add action=drop chain=forward comment=\
"defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat \
connection-state=new in-interface-list=WAN
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" disabled=yes \
ipsec-policy=out,none out-interface-list=WAN
add action=masquerade chain=srcnat out-interface=pppoe-client1
add action=redirect chain=dstnat dst-port=53 protocol=udp to-ports=53
/ip ipsec profile
set [ find default=yes ] dpd-interval=2m dpd-maximum-failures=5
/ipv6 address
add address=::xxx from-pool=O2 interface=bridge
/ipv6 dhcp-client
add interface=pppoe-client1 pool-name=O2 pool-prefix-length=56 request=prefix
/ipv6 firewall address-list
add address=::/128 comment="defconf: unspecified address" list=bad_ipv6
add address=::1/128 comment="defconf: lo" list=bad_ipv6
add address=fec0::/10 comment="defconf: site-local" list=bad_ipv6
add address=::ffff:0.0.0.0/96 comment="defconf: ipv4-mapped" list=bad_ipv6
add address=::/96 comment="defconf: ipv4 compat" list=bad_ipv6
add address=100::/64 comment="defconf: discard only " list=bad_ipv6
add address=2001:db8::/32 comment="defconf: documentation" list=bad_ipv6
add address=2001:10::/28 comment="defconf: ORCHID" list=bad_ipv6
add address=3ffe::/16 comment="defconf: 6bone" list=bad_ipv6
/ipv6 firewall filter
add action=accept chain=input comment=\
"defconf: accept established,related,untracked" connection-state=\
established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
invalid
add action=accept chain=input comment="defconf: accept ICMPv6" protocol=\
icmpv6
add action=accept chain=input comment="defconf: accept UDP traceroute" \
dst-port=33434-33534 protocol=udp
add action=accept chain=input comment=\
"defconf: accept DHCPv6-Client prefix delegation." dst-port=546 protocol=\
udp src-address=fe80::/10
add action=accept chain=input comment="defconf: accept IKE" dst-port=500,4500 \
protocol=udp
add action=accept chain=input comment="defconf: accept ipsec AH" protocol=\
ipsec-ah
add action=accept chain=input comment="defconf: accept ipsec ESP" protocol=\
ipsec-esp
add action=accept chain=input comment=\
"defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
add action=drop chain=input comment=\
"defconf: drop everything else not coming from LAN" in-interface-list=\
!LAN
add action=accept chain=forward comment=\
"defconf: accept established,related,untracked" connection-state=\
established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
connection-state=invalid
add action=drop chain=forward comment=\
"defconf: drop packets with bad src ipv6" src-address-list=bad_ipv6
add action=drop chain=forward comment=\
"defconf: drop packets with bad dst ipv6" dst-address-list=bad_ipv6
add action=drop chain=forward comment="defconf: rfc4890 drop hop-limit=1" \
hop-limit=equal:1 protocol=icmpv6
add action=accept chain=forward comment="defconf: accept ICMPv6" protocol=\
icmpv6
add action=accept chain=forward comment="defconf: accept HIP" protocol=139
add action=accept chain=forward comment="defconf: accept IKE" dst-port=\
500,4500 protocol=udp
add action=accept chain=forward comment="defconf: accept ipsec AH" protocol=\
ipsec-ah
add action=accept chain=forward comment="defconf: accept ipsec ESP" protocol=\
ipsec-esp
add action=accept chain=forward comment=\
"defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
add action=drop chain=forward comment=\
"defconf: drop everything else not coming from LAN" in-interface-list=\
!LAN
/ipv6 nd
set [ find default=yes ] hop-limit=64 mtu=1492
/system clock
set time-zone-name=Europe/Prague
/system note
set show-at-login=no
/system routerboard wps-button
set enabled=yes on-event=wps-accept
/system script
add comment=defconf dont-require-permissions=no name=wps-accept owner=*sys \
policy=ftp,reboot,read,write,policy,test,password,sniff,sensitive,romon \
source="\r\
\n :foreach iface in=[/interface/wifi find where (configuration.mode=\"a\
p\" && disabled=no)] do={\r\
\n /interface/wifi wps-push-button \$iface;}\r\
\n "
/tool mac-server
set allowed-interface-list=LAN
/tool mac-server mac-winbox
set allowed-interface-list=LAN
Currently, the NAS has IP 192.168.88.246. I can ping it from my laptop on wifi. However, when I try to open it in explorer, it fails. In network tab in the explorer I can see the NAS listed by its full name. But once I try to open it, the same error emerges.
Please note that I changed the lan port of NAS to verify it’s not port issue and completely removed Cap ax from the equation - to verify I’m connected to hAP ax3 wireless network.

