I have a new theory and it seems likely.
The server automatically runs demos have you ever thought about how many you get each day? Every time the game jumps for one or two seconds could actually be a demo stopping and another starting so already taking strain from other factors these could cause a crash by taking up too much CPU to quickly.
Testing this theory I have dèleted my garrys mod crash reports and all 300 non essential demos to see if this is the cause of my own crashing. I will perform a stress test when possible meaning being active on the server for more than two hours.
If anyone wants to try this out make sure you save any important demos and rename or move them to keep them safe and make sure in that demo you have what you need. If a demo will be needed for any action regarding action requests you should contact the staff reviewing this and make sure any evidence submitted is sufficient, it is your own fault if you delete something needed for a AR and I will not be help responsible as I clearly stated that this is a test and you partisipate at your own risk.
Any files necessary to running garrys mod can be re acquired by verifying files and remember.
There is no guarantee that this will work which is why im running the test on myself.