DaemonUmbra

As it has been for years now, CurseForge should be your primary (if not only) source for mods, and yes there are already loads of mods for 1.14.4. As it stands right now Optifine's compatibility with Forge is a single preview version that targets an old beta version of 1.14.4 Forge, so no guarantees of compatibility with the newer versions. Running Optifine and Forge together (assuming you have compatible versions of both) is the same as it always was, put Optifine in your mods folder like any other mod.

For a server: Run the new installer and change your startup script or command to use the new Forge jar. For a client: Run the new installer and edit your launcher profile/installation to use the new Forge version.

Installer is the only one you should be using. Universal and Launcher are things utilized/set up/configured by the Installer.

also you should be including the .jar file extension that Windows hides by default.

Does this happen with only Forge installed?

Please read the Logs section of my signature below and provide the appropriate log in the appropriate manner.

Where are you getting Forge from? Please give a URL. Where are you searching? Please provide a screenshot.

Shiginima User was banned for piracy

I'm afraid I'm not very knowledge able when it comes to Linux so I'm very much lost here.

You have all that with a default build.gradle? Are there no errors when you run gradlew eclipse genEclipseRuns?

Show a screenshot of your package explorer?

Did you make sure you got the correct version of Forge for the pack you wanted?

I see no reason for that to not generate a client run config. Run eclipse and genEclipseRuns, then click into Package Explorer and press F5

I mean please provide the build.gradle that controls the mod's configuration and build process

Oracle Java's role is changing, check out OpenJDK. I usually get my JDK from https://adoptopenjdk.net/

Where are you getting mods from? You know mods only work on the Minecraft version they were designed for, right?

Where are you downloading Forge from? Please give a URL

Provide your server.properties please?

I see 32-Bit Java and missing log appenders which I believe were a problem from long ago. Please post your code in a github repo

GradleStart no longer exists and you need to configure more than that to get Forge to load mods in dev. Please provide your build.gradle

This is not a full log, please provide your full debug.log from both server and client

Can I just have you confirm the URL you're downloading Forge from?

Please use one of the sites listed in my signature, Google Docs throwing formatting on top makes it harder to read

What do you mean by a start/stop loop? Please provide debug.log and possibly screenshots.

https://johann.loefflmann.net/en/software/jarfix/index.html