PC gaming or console?
LG do/did some pretty decent cheap 4k TV’s that are good for gaming: https://www.eurogamer.net/articles/...budget-55-inch-4k-hdr-tv-is-gbp400-today-7006
4k, 12ms input lag in game mode, basic HDR (though no HDR for gaming). It's last years model but if you can one of these then the 43" or maybe even the 47" are around your budget.
right now many of the budget tvs under £500 are worse than last years models. also cause they new they are sorta over priced. samsung 7100 seems okay but has very bad viewing angles i think the 7400 does aswell. hisense tvs have bad build quality and very bad support. many horror stories about. they seem if you get a good one they can produce decent picture though. thing is if it goes wrong your gunna be pulling your hair out.
i would deffo do some research as many of the sets have issues.