Bridge port "is already a slave" after updating to newer RouterOS versions

RouterOS Beginner Basics
16

What's the point of trying? At most, you'll solve other problems...

Given the rest of the configuration, the script to paste is this:

# fix *9 error (default "bridge") and set to default values ​​(they have never been set by the user)
/disk settings
set auto-media-interface=none auto-media-sharing=no auto-smb-sharing=no

# fix *2000011 error (default "LAN")
/ip neighbor discovery-settings
set discover-interface-list=LAN
/tool mac-server
set allowed-interface-list=LAN
/tool mac-server mac-winbox
set allowed-interface-list=LAN
# this is for 2 rules (input and forward), with same description
/ipv6 firewall filter
set [find where comment="defconf: drop everything else not coming from LAN"] in-interface-list=!LAN

# alignment with NEW default values on RouterOS 7.22.3 ​​(they have never been set by the user)
/interface ethernet switch
set 0 cpu-flow-control=no
/interface ovpn-server server
remove [find]
/ip ipsec profile
set [ find default=yes ] dpd-interval=8s dpd-maximum-failures=4

# remove unused datapath on wifi settings
/interface wifi datapath
remove [find]

and an extra script, not related to the problem, for use the new fasttrack, if the device support it:

/ip firewall filter
:execute "/ip firewall filter set [find where comment=\"defconf: fasttrack\"] hw-offload=yes"

/ipv6 firewall filter
:if ([:len [find where comment="defconf: fasttrack6"]] = 0) do={
    :execute "/ipv6 firewall filter add chain=forward action=fasttrack-connection connection-state=established,related comment=\"defconf: fasttrack6\" \
                                        place-before=[find where chain=forward comment=\"defconf: accept established,related,untracked\"]"
}

because this: