You might have noticed that no self-respecting Youtube Workshop Warrior in the US feels able to approach a machine tool that isn't equipped with the obligatory Kurt vise - or two would be even better. However, the real benefit of the Kurt vise and its myriad copies is the "angle lock" feature that pulls the jaws down as they are clamped. The tighter you make it, the more the jaws are pulled down. There are loads of indifferent copies out there and I bought one of those Chinesium versions a few years back. The angle lock part itself turned out to be barely functional, as the tolerances were so far out. I ended up remachining that bit but of course that's basically ladling lipstick on a pig.

If you can get a half decent angle lock type vise without having to cough up the full price of a new Kurt (best part of a grand), you can find a workable half way house. I got a 6" version from Arc Euro Trade last year and it's been fairly well made. Ketan's done a decent job of quality controlling his Chinese supplier there.
https://www.arceurotrade.co.uk/Catal...-Milling-Vices They also do a 4" version I see - and the price isn't bad. Shipping a POS lump of scrap cast iron from AliExpress over to the UK is an expensive business, which doesn't leave much for the "vise" itself..