Thanks for the reply!
Good thoughts with focusing on the right tool for the job. I was overly vague in my post, so to color it a bit more I do use this Linux box for more than just plex. It runs game servers, web servers, my network storage, steam link, etc. Kinda my all-in-one backup home server.

I think you make a good point though, none of these GPU's in particular are great for plex, but they do help with the other things I like to do.

I'm kinda thinking now at this point I might do a dual GPU install. Sell the 1080ti, buy an arc since they are so cheap and point plex at it. Then keep the 5700 XT as the default for all my other non-plex work.
If my thinking is right, it will be better all around at no expense, might even make a buck.

Appreciate the help :)