It works just fine, its your setup that is not working either on the phone or on the MT itself.
Here is an example of my settings for my iphone.........

I can only state what I have setup on my wireguard connections................
On the Server Router.
a. listening port on input chain to allow initial connection traffic. (port 9213)
b. route to wg interface for any return traffic for peer originated outbound using the server router for internet ( automatically created if you give the wg interface an IP address).

For SERVER ROUTER Wireguard Settings
Name = wireguard-iphone,
Listen port =9213 (matches input chain rule)
Private key (not used externally)
Public key = xxxxx to be sent to Iphone.

For SERVER ROUTER Peer Settings
- Interface name = wireguard-iphone
- Public Key = yyyyy this is the public key received from the Iphone
- Endpoint = empty (as i have no idea what the IP address of my IPhone will be !! )
- Endpoint port = empty (not applicable)
- Allowed address = 10.10.10.2/32 (this is the IP address I will put on the wireguard settings on the phone).

Finally..........
For SMART PHONE Wireguard Settings
Public Key = yyyyy The public key provided TO the server router
Addresses = 10.10.10.2/32 The address assigned to the iphone for the wireguard traffic.

For SMART PHONE Peer Settings
Public Key = xxxxx The public key provided BY the server router.
Endpoint = IP CLOUDname:9213 the name of the server router appended with listening port. ( tells the smartphone where to make the initial connection)
Allowed IPs = 0.0.0.0/0 ( which basically lets any IP assigned to the smartphone be relevant either assigned by coffee shop wifi or cellular provider etc..)

NOTE: I use the dyndns service provided by MT to identify the endpoint on the smartphone.

Yes, in my case the main router is a CCR1009.
Correct I use port forwarding to send the listening udp port to the LANIP of the second router (on the main router LAN applicable subnet). This main router LANIP is thus the same as the WANIP of the secondary router. Thus the listening port traffic hits the WANPORT of the secondary wireguard router and I use the input chain rule to capture the connection.

In my case the endpoint setting on the smart phone could be the IPcloud of the CCR1009 (main router) or the IPcloud of the RB450G secondary wireguard router as both will return the public IP that is applicable (in this case the dynamic wan ip assigned to the ccr1009).

What do you mean by gray IPs? I think this is where the trouble may reside!!

Please draw a network diagram as your config on the MT device is very confusing and ALL WRONG, and a diagram will help clear up some unknowns!!

Why is the output chain used and especially for the UDP port.
Why is the MT device which is your wireguard server port forwarding the UDP port.
It should only be using the INPUT CHAIN ?????
OR IS IT behind another device???

Finally you didnt do a good job of comparing my setup with yours.
Clearly the WIREGUARD peer settings are missing the allowed address!!!

YOU NEED TO show your config as the pictures are not that helpful.
/export hide-sensitive file=anynameyouwish

As stated, this is a personal problem that you have, and is clearly no longer related to the wireguard or router settings.
Your stubborn head is the issue preventing success.
Good luck!

Hi there,
(1) The WG interface may or may not get an IP address (optional, works either way).
It does not need nor should get an IP pool, dhcp server etc.........
/ip pool
add name=dhcp ranges=192.168.89.2-192.168.89.254
add name=pool1 ranges=192.168.90.128/25
/ip dhcp-server
add address-pool=dhcp interface=brHome lease-time=1d name=dhcp1
add address-pool=pool1 disabled=yes interface=wgHome lease-time=23h name=\
wgDHCP

(2) Why did you put the WAN connection on a biridge, normally not required?
Perhaps there is something I dont understand.
Also dont get this -- at least never seen it used before??
/interface bridge host
add bridge=brInet interface=ether1 mac-address=AA:BB:CC:DD:EE:FF
/interface bridge port
add bridge=brInet ingress-filtering=no interface=ether1

(3) I dont understand the very unusual non-standard use of interface list and interface members.
What prompted you to do this ?? More specifically what was the point of the include all line???

/interface list
add name=WAN
add name=LAN
add include=all name=discover

/interface list member
add interface=ether1 list=WAN
add interface=ether2 list=LAN
add interface=ether3 list=LAN
add interface=brHome list=discover
add interface=brInet list=discover

(4) Where in heck did you get those firewall rules? They are not even close to correct for anything.
Better off putting the defaults back in and only making necessary changes!

(5) Lets look at wireguard settings...... Assuming this is SERVER router (where the peer clients reside).
First thing for your android phone to work you need the IP Address given to the android phone it the android phones WG settings.
More specifically in the phones OWN WG settings (not the phone peer settings).
So you need to put an address here on the phone that matches up the allowed address on the router.
Lets say on the phone you use 10.0.30.2/32
Listen port not required
I put in DNS servers 1.1.1.1 and 9.9.9.9 as well, not sure what your phone has.
On the phones peer settings this is where you put the endpoint of the router.
I use the IP Cloud address of my router for this
I dont use keep alive
Its in the peer settings you put allowed IPs 0.0.0.0/0 (because we dont know what public IP your phone will have when you connect).

So now looking below, in the red on your router is where you would put 10.0.30.2.
The other two lines, not sure what they are for but remove them for now as they dont seem to server any purpose.

interface wireguard peers
add allowed-address=0.0.0.0/0 comment=Aurora interface=wgHome public-key=\
"xxx="
add comment=RobotArms/W7 interface=wgHome public-key=\
"yyy="
add comment=Motor endpoint-address=192.168.90.4 endpoint-port=51820 \
interface=wgHome public-key=\
"zzz="

Ive already pointed out what information needs to be put in both the router and the smartphone,
Ive also pointed out issues with your config.
Not much more one can do, until you decide you want to learn MT and not be so stubborn.
Wireguard works great.

@anav Wireguard is quite fun to use. I tested it behind two nats (double natted) and I had a thing i did not understand.
I opened ports on both main routers that directed to the main wireguard peer behind the network.

Whatever peer that initiated the connection would use a random port (I am guessing it was masqueraded) to connect to the dst-nated port on the other network
The receiving peer will use the dst-nated port all the way thru to contact the initiating peer.

If the ip of either wan changes the internal listening port of the mikrotik's wireguard configuration of the device behind this ip change needs to be changed on the initiator or the masqueraded port path will fail? (this is my guess, it just won't connect as the target peer and router will not see any packets)

otherwise it just works, this is amazing! I am so glad it got added to routeros

Of course, there is nothing new in what you are saying.
The peer client end has to know which WANIP to send the initial request too.
That is why using an MT wireguard server is handy because one can use the available IP cloud:port# as the address.
Otherwise one would have to get a dyndns name setup for the WANIP (unless it was a static Wanip).

It doesnt matter how many routers are behind the router with the most outward facing connection aka the public IP.
That router needs to port forward the listening port to the second router and the second router to the third etc.
The last router takes the port and uses it as INPUT CHAIN RULE to the router itself.

There is no random assignment of listening port however.