Addressing the subscribing part; I had similar requirements, so I started subscribing via FreshRSS while using a custom theme to give it a YouTube-like experience.
I shared the setup a few month ago here: https://lemmy.world/post/21381606
Edit: One of the benefits of using selfhosted RSS with a web interface is that it is platform agnostic.
That’s a valid question! The app is intended for less tech-savvy people, as such, the terminologies used are to accommodate those users. “Upload” would rather be “Import”, while “Download” would be “Export”.
I’ve shared the use case in a previous Lemmy post: