SInce your Samsung doesn't support Dolby Vision, you may want to consider a less expensive 4K streaming solution, such as the Roku Premiere 4K. I picked up one recently on sale for about $30, including the proper 4K HDMI cable.So I'm starting to get tempted by an Apple TV 4K, because my Samsung KS8000's UI for apps is...unawesome. But I have a 3rd gen AppleTV that I never use now, so I'm afraid I'll just be throwing good money after bad. I am not tempted to hook my ATV up to my Samsung because I would give up 4K HDR Netflix.
The other boggle is that the current ATV4K is a couple of years old. I'm one of those who doesn't like to buy something, if an upgrade is just a few months away...first world problems.
4K and HDR are important in whatever I buy to supplement my Samsung TV's apps. My Sony 900F TV has a pretty decent UI and apps, so that's where I watch my 4K streaming mostly.
EDIT, found the rumor that has me hesitating, from...fittingly...Macrumors!
Really do hope that there is a new remote. I'm not a fan of the one that came with my 3rd gen, and the current one isn't much better.