Ingress Filtering Questions + uRPF

es, someone allowed me to read MUM archives, very dangerous!!

https://vanphongre.com/, lets do the easy one first.

Q1. /ip settings set rp-filter=strict Or /ip settings set rp-filter=loose

I have a BELL FIBER Connection on a VLAN (not ppoee) and an EASTLINK basic cable connection.
According to the mum for dual or more wan assymetric i should be using LOOSE. Is there any harm to keeping it strict?
Could strict interfere with Ip routes to the secondary ISP email or other weird shenanigans?