My log file...
latest.log
I did try the method of writing something into the lithium config file as recommended in the release notes, but it didn't work either. I'm very suspicious it's Lithium again, as it mentions Lithium in the Java error.

So i tried it on CLient side and it also crashes. I loaded the client one time only with Lithium, only with C2ME and then Both at the same time. Here are the logs, if it helps:
https://pastes.dev/AzdwlwmYvx

Please use backports builds from our modrinth page if you still need to use 1.18.1.
It is still recommended to update to 1.18.2 as we are dropping support for 1.18.1 soon.