For a turret prop for games 6 or 7 UDIMs sounds like way too many. This depends on the resolution of each UDIM of course, but as @Joopson mentions throwing more resolution/UDIMs at it is probably not a reasonable way to solve it. In production, you will have a resolution limit that you will need to stay at/under, so making…
You may have to elaborate this to get a more suited answer. Because six textures with six different UV maps (UDIM or not) with the same resolution.. of course will give you a higher pixel density.. or using one six times bigger image in the first place (?).
My advice would be to make sure you have realistic expectations, and an efficient workflow-- before introducing UDIMs at all, let alone more UDIMs. UDIMs aren't a magic fix-all patch, you still need strong fundamentals or you'll end up working wastefully, and producing assets that are unnecessarily heavy. Just my two cents!
This is one of those situations where there's a real distinction between 'can' and 'should' You absolutely can use 7 texture sets on the turret and there's no reason to not use 7 texture sets on the turret if your use case justifies it i.e its big and important and you're taking full advantage of the resources you're using…