My apologies if this isn’t quite where this should be… COVID is keeping the family apart this Christmas, and so I am looking for ways to play games like Uno, Scrabble, etc., online with the inlaws in what would be a mixed computer environment (they have Windows, despite my protestations…). What I have found so far seems to be utter crap… flash games with endless pop-ups, etc… if anyone has any experience with this, I would appreciate it!
That crap will be gone by December 31st anyways. 
How about Roblox Uno?
Looks interesting! Thank you very much!
I think that Stardew Valley can be played online cross platform (PC and Mac). I understand that the iOS version does not allow for that.
Multiplayer entry at Stardew Valley Wiki and picture of multiplayer from there
It might not be the sort of game you’re looking to play with your in-laws but it’s super popular now.
Stardew Valley is also available on consoles. 
I didn’t come here to only say that though. Take a look at this! 
Have you tried Drawful, Quippage etc from jackbox.tv? We used to play this at parties, now we have a zoom set up with friends while playing. Not exactly the same as in person but still fun.