What is cleanroom: Cleanroom is basically forge, but supports java 21+, increasing tps by a lot and allowing new java arguments that help with tps spikes. It can be installed both client-side and server-side. Also decreases load times SIGNIFICANTLY, and decreases ram and cpu usage.
Download the cleanroom installer from GitHub (https://github.com/CleanroomMC/Cleanroom/releases/tag/0.3.4-alpha)
Run it, select Install Server, select an empty directory and click OK
Install Fugue and Scalar Legacy mod from curseforge (Also check if the modpack you are playing as Forgelin and phosphor, in that case remove Forgelin and install Forgelin-continous, and delete phosphor and install alfheim)
Go to the folder you installed Cleanroom on, change the Cleanroom jar name to server.jar
After that, right click on Libraries folder in the cleanroom folder, (if on windows 11 press show more options) winrar, and add to archive (you need winrar installed)
Now go to FMH, console, files, delete the server.jar then drag the server.jar from the cleanroom folder.
After that, drag the Libraries.rar zip you just made, then on FMH, press the 3 dots, and unarchive.
Then go to mods folder, and drag Fugue and Scalar Legacy (and delete forgelin and phosphor and install the alternatives I mentioned above, if your modpack has them)
Then go to Startup, and change java to version 21.
THE CLIENT JOINING DOES NOT NEED TO HAVE CLEANROOM TO JOIN THE SERVER
