can't rename saves and can't delete saves from load game menu

@StardustVoid  It's clear you use "save as" often, which is why you have so many separate save files, but they still shouldn't have reached an 8-digit hexidecimal number.  For reference, "My Saved Game 2,241,087,334" in your Main Menu screenshot corresponds to Slot_85944767.save, and 2,241,087,334 is 85944766 in hexidecimal (base-16, as in, the digits are 0 to 9, a to f).  Since slot 00000001 is not used by the game, the numbers match exactly, which I at least find interesting.

Anyway, somehow your game started counting at a much higher number than the Slot_00000030 in your other screenshot.  I don't know if this itself is the issue, or if the issue is simply that you have too many saves, but either way it's easy to address.  Move the entire saves folder to your desktop, open the game to create a new one, copy (not move) the most recent save to that folder (but no others), and rename the file Slot_00000002.save (seven zeroes, then a 2).  Don't copy over any other files yet; just see whether you can rename or delete the save.  Since you're copying the file, it won't matter if you delete the new copy, but if you'd prefer, you can experiment with older saves instead.