As people grow older they want less complexity not more, doubtful the aunt appreciates it as much as the op.
For everyone else looking to consolidate a settop box and tv to a no bullshit remote highly recommend
https://www.oneforall.com/universal-remotes/urc-6820-zapper#...
Gone are all the superfluous netflix or change input buttons that make your parents stuck and generate support calls.
You configure the remote for tv and when thats done you (optionaly) configure it for the settop box. At that point only the dedicated TV power button goes to tv all other keys go directly to the settop box and theres very few of them with comfortable size and best rubber quality i've seen in a remote ever.
The settopbox/tv compatibility list is not published online but spans decades and i had no problem setting up a noname one that wasn't even on the list.