How severe are the winters where you live? I've never been anywhere where you couldn't go out with proper clothing.
And I don't see much difference between books/ board games and screen time (except allowing them to browse youtube etc)
It’s as if all of the movies are using special effects drenched in CGI all of the time.
You can't alt+tab on real life activities very easily (generally).
There are plenty of other non-screen indoor activities. Games, books, being involved cooking dinner and doing chores, homework, etc.
At my house, we have a ton of craft supplies and my kids love doing crafts. It doesn't have to be expensive either. Old toilet paper rolls, cardboard boxes, pipe cleaners, coloured paper, glue. All very cheap and very fun for a kid.