Trying to get to the root of CTD

[MyX6031769]

Sorry for another CTD topic, but there are several cases I didn't found to be mentioned in similar threads (spoiler, working with "tai" command).

 

So, the story is; I had a playthrough 3 years long on one single character. Step by step I started to get more and more random(!) CTDs. While loading, moving in Boston areas, fast travelling, getting close to settlements, e.t.c. So a week ago I upgraded my PC (RTX, I know about weapon debris problem) and moved whole game with mods and saves to another hard drive. CTDs became unbearable - got only one save, that loads stable. Any fast travel ends with CTD right after loading (right after or few seconds more). Only thing that helped (!) - disabling AI ("tai" command) in main menu before loading. In that case game loads successfully, but as soon as I switch AI on, everything crashes.

So I decided to make a new start - reinstalled Fallout, redownloaded mods, created new char. Installed mods with Vortex, sorted out with integrated LOOT.

 

Now the fun part: I created a character, moved through the intro part (home-Vault 111-Thawing-Finding PipBoy). All worked fine, quicksave/quickload. But as soon I got topside, game crased. And it kept crashin stable on every(!) loading screen - sometimes right after load, sometimes character meneged to ascend topside.

With "splitting half" method I narrowed to mod "3DNPC_Settlers". While disabling mods situation was different, sometimes CTD on load, sometimes all worked fine, sometimes CTD after few seconds. Tested 10 loads on every disabling-mod action. CTDs were about 8 times of 10.

 

So, in the end, after disabling "3DNPC_Settlers", game wasnt crashing, I decided to go. Moved to Sanctuary, Red Rocket, Concord. All fine. Helped Preston, moved them to Sanctuary. All fine, quicksave/load.

 

And after that I decided to import blueprint of Redrocket from previous playthrough. Import passed, i pressed QuickLoad and BAM, game crashed! Loaded previous save inside Museum of Freedom with Preston, BAM, game crashed!

 

So now i have both saves, that loaded fine, causing CTD.

 

Tried settings with Papyrus, how Sim Settlement Perfomance article says, tried deleting inis, tried "high priority" for process. Only thing that helps again - is toggling ai off. But when toggling its on - crash.

 

What could cause such behavior? Is it a pathfinding problem? How could guaranteed working save stop working? Maybe there is some diagnostics?

Tried looking what files fallout4.exe accesses with ProcessMonitor: right before crash and right after toggling AI on, in "Hardcore0.log" following lines were added:

[03/20/2020 - 09:52:28PM] [hardcore:hc_managerscript <HC_Manager (0000080E)>]: OnTimerGameTime() aiTimerID: = GameTimerID_Sustenance @ 1.127009
[03/20/2020 - 09:52:28PM] [hardcore:hc_managerscript <HC_Manager (0000080E)>]: HandleSustenanceTimer()

 

what do they need?

Modlist is in the attachment.