- πΊπΈUnited States illeace
At least in Drupal 11 with the 2.0.0-alpha6 module, I don't think the missing upload button is the problem. The core Image field widget has a similar UI -- a file picker with no upload button. That said, there are other issue using this widget (see https://www.drupal.org/project/h5p/issues/3309418 β ), and with Drupal 11 it generates a WSOD because the file_validate_extensions plugin was deprecated in D10.
- πΊπΈUnited States illeace
Now that #3309418: H5P Upload widget PHP notices β has a fix, I can test this. It works OK even without the button, but you have to save the content (submit the entire form) to upload the H5P. I also agree with @paalj -- the H5P Editor widget also an "Upload" option and has generally a better experience. I'm changing this to "Feature request" but bumping down the priority.