I have your Minecraft Bedrock Server running. The Linux version.

Before 1.20.30 it was working perfectly for ages, years I think, its been a really long time.

Ever since 1.20.30 came out the local lan server no longer shows up in Minecraft.
I checked out the Windows version and that works but the Linux version no longer works. Its just not there anymore in any version of Minecraft.

Can you fix this or is there something I have to change to get it working?

I'm using a QNAP NAS to run the bedrock server on and its been running for years. 
I've been updating it as soon as the client says its an outdated server. Just copy/paste the files over and its all good.
Now, 1.20.30 came out, the usual download and copy/paste and now nothing. It just stopped working.
If I copy the old executable file over then it shows up but it says its an outdated version so it doesn't work but its showing up again.
I put the new version on and its gone again.

I tried the beta, 1.20.40 and that also doesn't show up.

Have you killed the linux server? I cant get it working anymore.