i did that partially. I have a bit user subscribed to many communities. Unfortunately that is a fully manual task - currently i don’t have an automated way of doing this
But only in the early stage. If you got it once, it‘s like cycling a bike.
Best to understand ist to create another account on another instance and then subscribe the same community there. Then you can check which posts and comments are shown how on the feed
Problem with you approach is, that you have an easier maintenance, but your users need an additional tool. Especially when grandparents should use this, you should stick to what is there.
In theory you could host a matrix server and install some bridges like whatsapp, discord, etc.
probably you would be able to create a matrix room and invite your granny via the whatsapp integration, your friends via discord, etc.
Disclaimer: I did not set up such solution - this just came to mind for your situation.
As far as I remember, Remux is the only way to have True 10Bit HDR…
When compressed, HDR is either removed or not really working anymore - at least this was consensus some years ago.