Am considering changing from Yahoo groups to Facebook
assuming it encompasses all that Yahoo offers (having
trouble with "files"). Any advice?
Facebook has a huge problem in that you can't go back and find anything. It's not designed for the retention of information. It's designed to be a short-term social media that just comes and is gone.
Groups saves your messages in an archive and has separate places to save files and photos. Information from the past can be recalled relatively easily.
If what you're talking about is transitory in nature and meaningless after a week, FB will work for you. If you need a repository of ideas and information, it's a poor choice. I'm curious what doesn't work for your group on groups.io?
YMMV
Dano
D R Stinson