Hello,
In Wireguard → Edit peer → Advanced settings, you can set a custom routing table, i.e. table 244.
Also, you can create additional routing tables and rules in Network → Routing → Policy Based Routing (PBR). For example, create a new Table ID 244, and add a static route 0.0.0.0/0 via the Wireguard interface. Then, on the same PBR page, create a new Routing Rule. There, for example, specify the source subnet as 192.168.10.10/32 and set the lookup table to your newly created table 244.
This way, the traffic coming from 192.168.10.10 will be routed via Table 244 which has the Wireguard interface as the default route.
Kind Regards,