It looks like a firewall issue. You either need to have a rule allowing the traffic arriving on the wireguard interface, or you need to add the wireguard interfaces to an interface list with an existing rule.
Ping works to the router because ICMP is allowed by default on the input chain.
If you want to provide full access, I would at the wireguard interface to the "LAN" list with this command:
/interface/list/member/add interface=WG-DOVER list=LAN
The above is for the mia-ro, you need to do the same-ish on both ends.