I have a Samsung TV now and have had LG's in the past. Both are very good TV's with the LG slightly better IMHO for picture quality. My Samsung has developed white spots here and there, not really noticeable when watching TV, but for using it as a display for art, photos, etc. I'd notice. It is several years old though and I'm going to replace it soon anyway, probably with another LG.
As for the built in Smart features, after you get all the username/password stuff loaded it works well. Just be prepared to have to re-enter them every single time the stupid thing updates. And you have to use the remote to enter them, takes for flipping ever! Especially if you have more than one streaming service. But don't skip the updates if you put it on the internet, that's how you get infections/hacked on your local network by not keeping everything updated.
Glare is a problem, windows, lamps, etc. Use a mount that is adjustable, left/right, top/bottom, you will need to tweak it to be able to watch TV.
For programming in the "art" it usually has a place to plug in a USB memory stick and has a built in slide show program in it's Smart Apps. Usually fairly simple to setup. Like the digital picture frames you can get.
As for mounting, distance, angles, etc. I've found these helpful.
From Sony TV web site,
"The recommended height for wall-mounted TV depends on individual preferences and seating arrangements in the viewing area.
In general, the TV should be mounted with the horizontal and vertical center lines at eye-level of the viewers.
In addition, each TV model has a different viewing angle specification, which is the number of degrees you can view the TV screen from off-center, and still see a clear picture.
Refer to the Marketing Specifications for the specific viewing angle of your TV model"
And a good calculator for distance for optimum viewing.
This TV Viewing Distance Calculator will assist you in discovering the perfect distance from which to view your TV in accordance with THX, SMPTE, and Visual Acuity standards
goodcalculators.com