@OABALB There's nothing alarming in your dxdiag, and the fact that your new save works (and your others aside from the main one?) strongly suggests the problem is with the main save itself. Can you load and save a backup copy of this save? Please use the manual method of recovery, and try the oldest backup if the most recent one doesn't work.
https://sims4.crinrict.com/eng/2014/09/recover-backup-save-game/
If that doesn't help, can you save your progress if you switch to a different household first? You can use "save as" to rename the save, so you're not potentially overwriting your main save. Here again, please test with the backup if the main one doesn't cooperate.
If that doesn't help either, then you can send me the save, but I'm not sure how much I'd be able to do with it. Upload it to a third-party filehosting site (Google Drive, Dropbox, etc.) and either post the link here or send me a PM. Please also list the name and location of the main household in case there's any weirdness on that end.