I tried to search the solution for this situation but didn't find one.
i have a 2 wan connection for example
wan 1 an ip 1.1.1.1/24
wan 2 have pppoe 2.2.2.2/24
and 1 lan have 10.10.10.1/24 dhcp-server, and pppoe server with different pool 12.12.12.2-12.12.12.254
how i config LAN dhcp-server traffic goes through wan 1 with a specific network 10.10.10.1/24 and wan 2 traffic goes through specific pppoe-server pool 12.12.12.2-12.12.12.254 (or specific network)
notice that there have no concern with both 10.10.10.1 and 12.12.12.2-12.12.12.254(or specific network) if wan 1 goes down then no effect to the other hand pppoe-server and only dhcp-server effected by wan 1 and pppoe-server effected only when wan2 goes down

i already have dhcp and pppoe-server with 1 LAN via wan 1(dhcp-client) it is working correctly
sorry for my bad english

ohk let me tell you with my knowledge i try to config this with mangle marking route but when i enable the address(or interface) of wan2 internet will extremely slow down that disturb DHCP-server
here is rule there have no bridge just for writing
i have also fast track dummy rule in mangle