Hi, recently i made a few tries to make a portal, but had a game crash followed by the inability to load the world

There is a Crash Log:
crash-2024-12-02_01.10.15-server.txt
There is a Game Log:
latest.log

looks like there's a mod in your modpack adding a structure with a backslash in its name
we found that those tend to crash things just today with cass, there's a fix already, should be included in the next version to release

Thanks for reporting, should be fixed in 2.3.3.