Attached are two crash reports from two seperate players, one on windows the other on mac. They both seem to have the same error causing the crash, not really sure what it means.
These crashes occur every hour or so for both users. Other players on the server don't seem to have this issue, and the crashes started occurring when larger scale contraptions/factories were built.
Any help will be much appreciated!

crash-2021-12-05_17.11.35-client.txt
crash-2021-12-13_20.23.39-client.txt

Can confirm both another player and I playing create above and beyond are getting the same issue. For me I crash once every hour or so. He ends up crashing almost every 5 minutes sometimes. It only started happening once we had built large contraptions with create in the same area.
It feels random at what point or area it occurs and I cannot pinpoint it. The modpack is becoming unplayable while it crashes this frequently.

I cannot seem to find much information online on what could be causing this, most players with the same issue seem to blame optifine/optifabric. But neither are present during our crashes.

To add to this I believe the crashes were occurring at least on version 1.2 if not before. The 1.3 update didn't seem to change anything.

crash-2021-12-20_00.09.45-client.txt