Thanks @Sob, will read it right now.I didn't read it all, but DHCP gateway can be easily fixed using lease script:
viewtopic.php?p=899132#p899132
/routing table add fib name=ISP1
/routing rule add action=lookup-only-in-table src-address=10.22.22.33/32 table=ISP1
/ip route add dst-address=0.0.0.0/0 gateway=172.217.162.206 routing-table=ISP1