Stuck on LUA Started is a common issue when joining a server, here's a list of fixes that may help!
- Most of the time waiting for GMOD to load can fix this issue (let it load, do not tab in and out).
- Reduce the number of mods downloaded.
- Clear download cache & verify integrity of files.
- Change to a different Beta (x86-64 chromium + 64-bit binaries, Dev branch, and Pre-release branch).
How to verify files?
https://help.steampowered.com/en/faqs/view/0C48-FCBD-DA71-93EB
How to clear download cache?
https://help.steampowered.com/en/faqs/view/6AD7-820D-8BE5-E51F