A belt sander is more for shaping than smoothing. If the floor is already smooth and just need stripping then its too aggressive and you’ll bite chunks out of it.
I think the most important attribute of a sander is effectively containing the dust.
AEG, Matabo and Maffel 150mm random orbit disk sanders all have the same internals, have a good dust port that fits well to an extractor and have a greater range of orbit sizes (between 2mm and 6mm) than much of the competition so you’ve got options to remove more material or work more gently. Hooked up to a good hoover you’ll be able to work pretty cleanly
The AEG is cheapest but harder to find in the UK. Probably not worth you’re while paying for the Maffel. The Matebo is in the middle and over the AEG benefits from a easier to use dust port, the AEG one takes a bit of bodging with bits of pipe and gaffa tape to get good fit.
Avoid any sanders that don’t have a standard, circular dust port. Anything a propietroy shape you’re only going to be able to use with a silly little dust bag (which is practically useless)