Next item! 
It seems version 1.1.11 is causing pretty wicked stuttering for me. While standing idle I'm getting the expected 70+ FPS, when moving it's dropping into the 20-30 FPS range and is causing a 'stop motion" sensation.
My hunch, knowing nothing at all, is that it's probably related to the generation of loot ranking as I move throughout the map and get closer/further from loose loot spawns, containers, etc.
I tested against version 1.1.8 which doesn't seem to introduce the same performance issues.
I don't see anything that really stands out in the logs but I'm more than happy to assist with any ideas you may have.
Display More
My work is never done!
You're right that new stuttering is almost definitely related to loot ranking. Fortunately, that isn't nearly as much code to sort through. I'm fairly busy the next few days, but I'll try to improve it by early next week. In the meantime, setting destroy_loot_during_raid.loot_ranking.enabled=false should restore the performance from 1.1.8.
There is an easy way to generate log data that should confirm our suspicions:
1) Set debug=true in config/config.json
2) In BepInEx\config\BepInEx.cfg, change line 48 to Enabled = true
3) Restart the server and reproduce the issue in the game. A new console with bepinex messages will also appear when the game starts.
4) In the bepinex console, you should see a lot of yellow "Waiting for next frame" messages after the stuttering happens (having multiple monitors helps with this, but you can ALT-TAB out of the game to check). I attached an example of what it looks like for me. If your cycle times in those messages are more than ~20ms, that definitely explains the stuttering, and it means my code is trying to do too much per frame.
5) Exit the game and share BepInEx\LogOutput.log before starting the game again.
Another thing that will help me understand the issue: are you significantly increasing the amount of loot or bots in raids compared to vanilla SPT?
Thanks for helping me troubleshoot!