Generate photo gallery
List user submitted post as classified based on category
List out user submitted files like MP3, Video, PDF etc.
Get testimonials & feedback from users and display them
User gallery tab at Ultimate-Member & BuddyPress plugin profile page
Full controls over the submitted post by user at frontend
Use shortcode to generate forms which let users to submit custom fields included with YouTube or Vimeo URL, Video, Music, Documents and so on. All submitted content can be public or private with user's dashboard so that member can edit, delete the post. Options for administrator to make it public only after approval.
Don't worry about the shortcode tutorials. The basic generation of form & gallery can be achieved by using gutenblock editor. You can also check shortcode generated there which can be modified as to your requirements.
You can let user just to submit URL of video which will automatically generate required thumbnail and display them as required.
You can restrict user submission on number of files, type of files, post approval, security check , form submission and many.