I was the steamlink app on Apple TV and I haven't had any issues with garbage popping up and interrupting me, and I haven't made any tweaks to Windows. Just letting you know in case you'll find it useful.
Yeah, I can't say I've noticed any latency though, as long as I've got an ethernet connection set up. Also a good idea to turn on whatever your "game mode" is on the TV. I use one of those flat ethernet cables and run it under my living room rug to my TV.
I imagine using steam in big picture mode would be equivalent if you're not streaming though. Maybe it's something else, I just can't remember a Windows pop-up ever interrupting my gaming whether I'm playing on my TV or not.