After the last mod update (3.0.34) , there are no other planets on the map, and the requirements for space age research have changed (planetary research has disappeared)

you need to disable certain space age settings.
They are designed for nauvis planet run or vanilla+ run.
for example, SA4 or SA8

Did you default "on" some new thing that should be off? I don't use the mod but I've been looking at a save from someone who got unexpected errors after updating on Discord.

SA8 - already disabled
SA4 - set disable now.

It's working. Thanks)

Please post the setup instructions on the factorio mod page