Custom Dimensions dosent work

When possible, attach your MCreator workspace (preferably a minimal example workspace required to reproduce the bug; use File -> Export workspace to a shareable ZIP...), game or build logs (full logs, do not crop them, in text format, screenshots of logs are not acceptable) from the Console tab or terminal and steps to reproduce the bug in your workspace. If logs are long, use service such as Pastebin to host the log and provide the link to the log from the ticket. Please specify which mod elements to check in your workspace too, if applicable.

Especially logs, without logs, I can't help

Delete the entire <your user home folder>/.mcreator/gradle folder, create a new workspace with the same generator version as the version of the workspace failing, after the setup of this new workspace is done, open your current workspace, and click Build & run -> Build workspace, then Build & run -> Reload gradle project and then Build & run -> Regenerate code and build.