It looks like it was the MTU setting after all - however, not on the wireguard interface, but instead the bridge. The following was the fix:
uci set network.cfg0a0f15.mtu='1380'
It looks like it was the MTU setting after all - however, not on the wireguard interface, but instead the bridge. The following was the fix:
uci set network.cfg0a0f15.mtu='1380'