I remember when AAF was crashing to desktop and corrupting save files and the fix was to enable write to external file = TRUE … it is now standard in AAF.
My current save file, that doesn't crash is 36,767 … using 2,083.9mb RAM, 12.6% CPU, 1080TI power usage is 5.7% … if any of this data means anything (I know when mine was crashing, it was more towards 40mb and over 3gb RAM....)
I also noticed that my save file that got past 42 mb basically refuse to load Bunker Hills now, 42.993 work fine, anything over 43 mb just CTD on approach.
I tested without Sim Settlement 3 in 1 / Conqueror and that same character save went down to 20 mb, which is a bit insane (but I did tell Conqueror to start max level which might not be a great idea), it also removed the crash to desktop on save.
Looked at my first save, still not in the world just in the Sanctuary underground shelter at 29 mb, that's a bit high for my taste.
I do think you are on something there with external file saving, because for the moment I think the amount of data from Sim Settlement being saved in the save file is probably overwhelming for the underwhelming Creation engine.
Just worked 2 nights on my "Player base", so I guess it went up the small bit to hit the "death cap" during that time, a bit sad though, at least there is always Settlement Blueprint to send it to another game.
EVGA 2070 RTX
16gig of Ram
Samsung Evo 256 & 1TB SSD
Note that last time I played with Sim Settlement and I built a few settlement I was on my old i5 2500k and I got the same issues, thought they were just related to my kinda aging pc at that point, not so sure now.
Load order attached
save file when I can send it, sadly can't due to new forum account.
Still love the work Kinggath, you're definitely the king of Fallout 4 modding. :p