So I had a very interesting playthrough regardless or not if I bugged my save. My problem is that I completed the Nuclear Option (Minutemen) quest which triggered the cutscene to play and eliminated the Institute, I did not do the secondary objective very intentionally during the mission itself. Now every time I try to talk to Preston, he responds with the Dialog that occurs after the bomb detonation (IE Holy [censored]..). I had several instances where he said the exact same dialog and it doesn't seem to progress past it regardless of what dialog choices I choose afterward. First is after bomb detonation, second is after the bomb detonation after I completed the exact same dialog the first time, third is after I fast traveled which officially resulted in the quest completing and I later found him at Sanctuary Hills where he still says the exact same thing.
To my understanding, there's suppose to be a quest that leads up to destroying the Brotherhood next but I have no way of accessing that because of Preston's repeat dialog. It also cuts Preston off as a companion for me but I really never used him for that anyway.
I did a few key things that led to that point :
-Sided with Railroad during the Molecular quest to get into the Institute
-Did not advance on the Railroad quest afterward, instead did the Battle of Bunker Hill and ended up deactivating two synths before saving one which resulted in engaging the Courser
-After the Battle of Bunker Hill, was dismissed from the Institute by Father
-This also triggered Burning Cover, removing the Railroad from play as well which directed me towards the Minutemen
-I did the initial Brotherhood of steel quest at Cambridge police station but didn't follow up with it. I didn't accept Danse's offer to join, nor did I report to Cambridge when the actual Brotherhood force arrived.
-I failed the two brotherhood starter quests when the Institute attacked the Castle
-Fairly standard Minutemen stuff up until after the Nuclear Option was complete. This is where Preston got caught in the infinite dialog loop.
-Additionally, I went to the Railroad HQ just to see if they'd have an aftermath which resulted in them being angry at me destroying the Institute without evacuation and turned all of the Railroad hostile towards me. This of course resulted in Desmonda and Deacon's death.
-So that leaves Danse who I visited at Cambridge. He seems to fully acknowledge that the Insitute was destroyed and thanked me for that, and also mentioned that he was disappointed that I didn't do it with the Brotherhood but the Minutemen instead. This is the part that I found really strange because to my understanding, the Minutemen is suppose to ally with the Railroad and end up destroying the Brotherhood of Steel.
-Knight Rhys, and Scribe Haylen seem bugged. They're both present but they mention events that didn't actually occur. For one, Haylen "thanks me for sparing danse and disobeying Maxon", and on the other hand, Knight Rhys refers to me as "Paladin"
I tried the standard dialog curing things like saving and reloading, reloading in general, fast travel and speaking again, waiting elsewhere for awhile then speaking to Preston again, even continuing my playthrough for a bit and then coming back to Preston later. He does seem to give out new quests still, as well as completing the turn in for older quests. So I don't know, I also tried to look up this problem on google and there seems to be only one other topic about it but it didn't have any resolution.