1.37 Patch1 - Untagged traffic on P3 merged with VLAN on P2

Well the problem is complicated when you have two static IP's that are the same even with different MAC current firewalls and router hardware don't do outbound MAC by IP for session tracking and then you got the problem of if both IP's need the same port inbound which can't happen outbound tracking yes but thats likely not going to happen I fact its how my CGNAT works that I made a simulator of a working model

https://bridgemode.base44.app/CGNAT

so your going to have to change IP's for this to work from what I can tell you can't change anything on the unmanaged switch so you have to change Switch Port 2 devices IP