Surprisingly few new unique systems added in the last 4 or 5 DLCs, but they did add new inline script calls for habitable worlds, so that's neat.
Code may not be backwards compatible with 3.11 or older, I don't know.

Updated to include the update for Shallash.
It's shorter than my fix, and also keeps it from spawning inside the FE's borders, so I swapped to their code.
The NAND call is weird, considering the actual limitations in spawns, but W/E.... including it in the NOT would have worked the same as far as I understand.

Updated for new systems in 3.11
Allowed for behavior editing on recently exclusive systems (0 = mutually exclusive, 1 = force spawn)
Changed organization for future sanity.

Rather than have 1 file with all the changes that is hell to sort through, each vanilla file is given its own mod file for ease of reference and updating in the future.

On the off chance that new systems were added for 3.9, they have been added to the mod as well.

Ideally fix a possible issue I did with the upload last time I tried updating. Also separated the overlord overwrites so it can be edited to allow for them to be on for MP with an imperial fiefdom. I guess?

Ok, so changing spawn chance wasn't enough, I completely removed every thing other than 'base = 0' from the usage odds to double down.
Update: This appears to have worked. Also it's useful to actually check through all the relevant code so you know how many systems you're expecting. Chosen's cluster has 5 uniquely named, semi-rich systems (4 connected) plus 4 more random systems thrown into the mix.

Added overwrites for broken spawn of Overlord systems. Technically I just set spawn chance to 0 and removed all the country data from each, and I'll test that this doesn't break things in a new way.