After again wasting my time for a couple of hours I am relly mad and want to report this tedious issue.
Whenever I open a subtitled project in the editor to reposition the subtitles, there are simply no text layers or anything else besides the video layer.
I tried multiple times in google chrome as well as safari - same issue. I've had plenty of problems with trimming videos in the past as well as the subtitles function not uploading the video, but if it worked, editing the subtitles afterwards never was an issue - until now