[2021] HELP - blue screen/saved game won't load

That sounds like maybe a simulation error. Before loading your save, open Options and find the Loading Screen Mod on the list on the left. Then find its Safe Mode options and enable them all. Then try loading your save. If it works, save as a new file.

If that doesn't work, I recommend you post on the official support forums. It's a lot easier to look into things there, since you can attach your output log and savegame to a post.

https://forum.paradoxplaza.com/forum/forums/support-bug-reports.879/