LashedLime on the github page says intellijidea not supported, but it seem to work pretty well, whats the problem?
It says it's not recommended, but yeah it mostly works. Known issues are:
Eclipse formatter/cleanup rules don't work at at all in IDEA, so you have to use the ./gradlew spotlessApply command manually.
IDEA has one known issue with Gradle configuration cache. You may have to change this setting to work around it and make Gradle usable again. (Though, to be fair, there are a lot of other issues with Gradle's configuration cache that aren't exclusive to IDEA.)
LashedLime if not intellij what ide do i use?
The recommended IDE is Eclipse. VS Code (or any fork of it) also works fine.