Most of them are probably referring to the fact that Mojang ships a version of Java with the launcher, however this version is absolutely ANCIENT and is not registered with the OS at all.
You would get this error running Vanilla 1.14.4, Forge has nothing to do with it.
Also you do know that any mods that require a server-side component won't work on Realms, right?
Your issue was that you were missing mods.toml, now you've made a new issue for yourself.
Look at the console, what does Gradle complain about above the final error?