Oh that sucks, but also doesn't sound like the normal behaviour most are experiencing with the game. Myabe try verification of the game files. Almost sounds like somthing on your end causing issues.

Id still reccomend making a topic on the Larian forums or yo their support team. They'd likely either have more info or potential solutions for your specific issue.

Cause i had 724 quick saves when i completed my first campaign run of 64ish hours and never experienced any abnormally long load times or save file courptions.

Worst i had was a bricked long rest cutscense that i was able to circumvent via clearing any pending new dialog options in the camp before resting.