This is good advice but if you're looking for something fancy like HDR or DV you will be dissapointed as (in my experience) digital signage displays often lack those features.

I have a big 4k tv that was destined for a sports bar but it was slightly damaged, got it for a great price. Sadly it doesn't have HDR either, but it is an older model. Anyway, its great as in there's no WiFi. There is a network port but there's no streaming apps or anything installed on it. I use it paired with an nvidia shield and a nakamichi soundbar and have been enjoying the experience.

But I digress, look for business displays