(FO4, Series X) Game crashes whenever there's any attack at any settlement (when I'm there)

I love this game!

I have exactly 707 hrs, 59 mins logged on my second playthrough and as of today this is a new issue. First playthrough was on Xbox One (550+ hrs) and crashes were pretty common but much less so on the Series X... until now. I have zero mods, no CC installed and never have. Every settlement in the game (including all DLC) is built all the way up with no exploits. Plenty of everything- food, water, defense, entertainment, the works. Everybody is happy and so was I. The only change is that yesterday all but two settlements were complete. I spent all of today doing those last two, and now any settlement I go to crashes if there is any kind of firefight, even if it's just a bloodbug or two. I tried a hard reset, but nothing.

This is a view from the roof of the house at Kingsport Lighthouse looking down at the random encounter spot (during a rad storm) moments before it's going to crash. Every location since Sanctuary was first built has defenses like this with no issues (just lots of bodies.) I tried taking all the turrets down, but it still crashed. (It's not one of the last two I finished.)

Can anyone help me out, please? I'm still doing Far Harbor and I'm only up to The Glowing Sea in the main story. (I enjoy taking my sweet time...) Any suggestions would be greatly appreciated. TIA