Maybe it’s worth giving it another go, with a reduced scope? AFAIR the most controversial part was the None aware index access ?[ ]. The ?. and ?? operators do provide quite a lot of value on there own. ?[ ] could always be done at a later point.
As PEP 505 suggests three new operators and that might be a bit much for a single PEP would it be better to create separate PEPs for null coalescing and null aware member access? Or if I move forward with this keep it in a single PEP for these two suggestions?
It’s up to you and anyone else who wants to take this on. Since PEP 505 was technically deferred you could ask to be made a co-author and resuscitate the PEP. Otherwise you have to ask yourself if you think a single PEP has a better chance of being accepted than two separate PEPs?