Upload and export videofiles with transparent background (with Alpha)

Hi everyone,

I'm working on an e-learning project in Danish, where we have educational videos featuring a presenter in the foreground and PowerPoint slides in the background. The presenter is already keyed out (transparent background), so I'm looking for an AI service that allows me to:

· Upload the presenter layer with transparency intact
· Translate, dub, voice-clone, and lip-sync the video into English
· Export it in a format (e.g., ProRes 4444, .mov, WebM) that keeps the transparency so I can easily place it back into my Premiere Pro timeline without issues.

Is HeyGen able to do that, with any of their plans? Alternately, with service should I use?