Re: MELE saves are reverting to old saves
The standard save location for LE1 is "C:\Users\>Your user name<\Documents\BioWare\Mass Effect Legendary Edition\Save\ME1\>Character Name<" (respectively ME2 & ME3)".
If the game saves correctly there should be a file with the time stamp matching the time you saved in game. Is that the case?`
If not, look at this post and in particular at the point "Disable Controlled folder Access of the Windows defender"
If that still don't helps search your computer for files with "*.pcsav" file extensions and list the locations you find them.