Copilot is hallucinating. JDK 21 is the required and only supported JDK for Mendix 11 — Mendix dropped Java 17 in the move to 11. So JDK 21 + 11.10.0 is the correct combination, not a broken one.
Your actual error is a crash inside Studio Pro's own build tooling (JavaDeprecationParser), triggered by malformed Gradle build output not by your JDK. delete the deployment folder and .mendix-cache
Clear the whole %USERPROFILE%\.gradle folder, not just the cache.
Check for a rogue C:\Gradle folder and stale GRADLE_HOME / old JAVA_HOME env vars — Mendix 11 expects its own bundled Gradle 8.x.
In Edit → Preferences, confirm the JDK points at a clean full JDK 21 (Eclipse Temurin), not a JRE or partial install.
Then open again still if there is any error check by creating a new project! I hope thisn helps
It's probably hallucinating.
We upgraded a project from 10.24.13 to 11.10.0 recently and it has been working fine since.
Did you try excluding custom java actions if you have any?