As an update, I and others are currently working to ensure VisualEditor (and Parsoid) will be included in the upcoming 1.35 LTS release. I expect that it will be in unstable/testing by September-ish.
@legoktm This is excellent news. September time frame looks comfortable enough to get any FreedomBox changes ready and thoroughly test upgrades from Buster. That is around the time we want to start testing upgrade paths to Bullseye.
MediaWiki 1.35.0~rc.0 is in experimental now, and I'll be updating it regularly as new MediaWiki releases come out. Please let me know if you run into any issues!