Lagging very badly in Limbo. Can exit the world, but when I try to reload, the game freezes and I need to kill it via the process manager with a KILL signal. Loading the game up, I go back into the Limbo and the same process repeats.

I see you've had multiple reports now about Limbo causing lagging/freezing. It does not seem to be fixed.

Using version DimensionalDoors-4.0.0+beta.6-27.10.2021.jar

8dac8ce, 8c84d83 and a21073f all fix issues related to what you are experiencing. I will leave this issue open until the next release, but please mind that this is fixed in dev.
If you would like a dev build you can join our Discord and ask around, someone there will likely be willing to provide you one. You can also dm me for a dev build.

Same issue here. Same version too.

IS the latest dev commit okay to use? @CreepyCre

It probably is okay to use, though you'd have to ask Waterpicker to be sure. I'd just try it tbh.