I’d say it depends partly on your floors/where you’ll be using them.
Ours came from Decathlon and went for Hexagonal/rubber coated – don’t roll off into things, a lot more gentle on your floor if you put them down a bit hard, since they don’t roll you can use them for some extra exercises.
Someone on here recommend https://wolverson-fitness.co.uk and their dumbbells seem a chunk cheaper than decathlon (and you don’t have to spend that much for free delivery). My “black series” cast iron kettle bells came from there are nicest I’ve used.
Again on advice from here we’ve got a mix of dumbbells and kettle bells in alternate weights – eg 5 and 10kg dumbbells and 8 + 13 kettlebells gives more variety in exercise and weight choice.