DaemonUmbra

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

hm is a TERRIBLE mod ID, change that

You're mixing the 1.12.2 and 1.15.x build.gradle files without understanding them. At this point you'd be better off making a new 1.15.x project with a fresh MDK and take the opportunity to rewrite the mod, as a lot has changed in both Forge and Minecraft itself.

The filenames of one or more of your mods suggests you got them from a repost site. Please read up on the StopModReposts project (link in my signature) for info on why this is a bad thing.

This time post debug.log, not a copypaste from the console window

That'd do it

Ok then it sounds like the server might have crashed. Please provide debug.log using one of the paste sites in my signature below.

Did you start the server through a batch/shell script or did you just double click the file?

What do you mean by "Forge Interface"?

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

It doesn't download as a zip unless something is wrong with your browser. The most likely situation is that WinRAR is hijacking the .jar file extension that should belong to Java. Run JarFix once and try again.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

If you're referring to adfocus, just make sure you only click the "Skip Ad" button in the top right. Otherwise, exactly what site are you being sent to? Please provide a link

Can you provide a fresh log?

You should never give more than half to a single program, so give it 4 at most

That 8 is shared across your whole system, you can't give all of it to Minecraft.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Not wanting to support a version that is old as balls is not elitism. And you're not going to find a pre-setup workspace, that would require redistributing Mojang's copyrighted material that is Minecraft's source code, which is illegal, ForgeGradle exists for a reason.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

I've seen this error when the Gradle Daemon(background service) gets corrupted

I'm fairly certain the files in question are in a place that isn't supposed to be backed up, I know you've stated that you're not using Git and I urge you to reconsider, but if you insist then I suggest you look at the .gitignore file regardless to see what files, file extensions, and folders you should ignore when making backups(if possible). Again noting that if you used git these items would be ignored automatically as long as you included the .gitignore file

The installer accepts command line args, you can check them with --help Though I can tell you right now that --installServer is probably what you want

Delete your config folder