Had to replace the serialization library between frontend and backend again. I do not like ScalaPB's update and documentation policy: They introduce undocumented breaking changes with patch version numbers. This has now several times during year I watched the project. I know they are technically still in their alpha but it just makes it unusable. Now I'm using boopickle.
Solidified the UI concept. I am quite happy with how things look. Now I "just" have to get them working properly.