I have long considered buying high end tvs just to use as slide show viewers in my house. I could probably justify it at this point with the number of available high quality images and the quality of screens. But I would really like a 250 ppi+ screen that is 40+ inches to pull the trigger.

I've created an AppleTV app that uses IIIF (technology behind Art Institute of Chicago image release) that was based on this. Though this content area was historic maps [1]

[1] https://www.jack-reed.com/old-map-room/

you might want to consider the Samsung Frame TV:

https://www.samsung.com/us/explore/the-frame/highlights/

43" at 4K is 102 PPI, so I guess you would need a 16K TV to get 250+

I'd be careful buying Samsung TVs. They will probably release an update that injects ads into the UI at some point

https://gist.github.com/peteryates/b44b70d19ccd52f62d66cdd4b...

Or just use a third party device and skip using their software entirely. Smart TVs basically universally suck.

8k @ 40 is 220 ppi, so getting well into close enough range.