I encountered that kind of problem on a pal va4 megadrive with rgb bypass installed as you did AND the CXA video amp removed. I saw on your picture that the CXA is removed too am I right ? If so, try to put it back. It seems that some people had the same problem of a machine working for 2 hours and then won’t boot anymore. It’s linked to the missed CXA. This chip seems to do more than video amplify (maybe a clock relation).
The consoles are not dead I’m pretty sure about it.
Try to put the CXA first and then see.