LG make OLED for most manufacturers and seem to be the biggest OLED producers, but it's a very tangled web of supply and there are other players. Even Samsung have started making OLED TV panels now, after years of QLED (which is Quantum LED, NOT OLED even if they use naughty fonts).
Personaly, I love OLED screens and think they give fantastic results. Then, I do like watching Space Ships and Laser beams - exactly the sort of high contrast images that favour OLED. If you have a lot of ambient light in your room then LED may well be a better option as they're brighter.
I'd say that the essential acccessories for a TV are good broadband and a reliable wall mount. The latter can be found on Amazon for £50 or so, which is worth factoring into the budget IMO. I used one of these:
https://www.amazon.co.uk/gp/product/B01AYBLPNA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1It's very strong indeed, I tested it by getting a 10 year old to do pull ups on it before I mounted the TV
