Help! I have over 150 hours into Fallout 4, and I think I may have saved the game too many times...

I tried to play a week and a half ago, but when I fired the game up on my Xbox, it froze once the main menu loaded. No big deal right? Just close and reopen. Except it did the same thing the next 5 times I tried to play, each time freezing on the main menu (no selection, audio buzzing, full on freeze). I called Microsoft Support, and they suggested I delete the local game save and resync, thinking the problem would be a corrupt file. So the syncing took over an hour (save file is 1.4GB, red flag?) but I still get the freeze at the same time. They suggested I remove all saves and start over, and I told them that's not really acceptable to me. So they said they can't help with a specific game's save issues, and directed me to the Bethesda phone support (which goes to voicemail, and the voicemail is full). I managed to get Bethesda support to email me back but unfortunately they're saying that they can't access my save file to see what's wrong, so they recommend I start a new game or contact MS support for help.

I've explored almost every location and was about to choose which faction I'd support (haven't finished the main story), so I don't really think starting over is going to work. I'd rather just walk away from the game than start over. I know I probably screwed up with the saves but never would have thought the game would allow me to screw myself over like that.

Is there anything I can do? Any way to extract the save file and modify it, say deleting all but the last couple of saves?

Anyone run into anything similar? Help!