You're not going to get LS50 in a flat panel. But you can certainly aim for something pretty good.
The KEFs seem to have had good reviews, and plenty of people are using them as Atmos ceiling speakers, but they're not the latest technology - about 10 years old now? They're probably near the top end of what can be achieved in that form factor as a passive speaker, but something active with DSP is probably going to be more effective.
If you were looking for a fully wall-mounted surround system, the KEFs might be one of the best bets - multichannel active options are limited.
But for 2-channel, maybe consider these Ikea Sonos things Amir recently gave a strong recommend to:
https://www.audiosciencereview.com/...symfonisk-picture-frame-speaker-review.25139/
Hard to find KEF measurements, but some here:
https://www.soundandvision.com/content/kef-t305-speaker-system-ht-labs-measures