Thanks, I think the long cage derailleur with only a 39 chainring in front leaves sufficient clearance. Potenza is 11sp, I suppose the sprockets from the cassette cannot be mixed use as 10sp?
11T sprockets in general are different thickness so if you were willing to do all the measurements and find a spacer / have a spacer made up, a loose sprocket might do - but the bottom 3 sprockets in Potenza are a triplet, not loose sprockets so you would have to use a third party sprocket like Miche.
As Bikerjulio says, the issue is sprocket clearance. You could use an extender to run the RD further away from the cassette so allowing big sprocket clearance but this is always at the cost of accurate indexing in the middle and smaller sprockets, plus the extra leverage exerted on the original hanger and on the upper pivot of the RD are not without their own ramifications.
As ever when you try to work outside a designed spec, a key question to ask yourself is one of "how many compromises in performance or longevity am I willing to accept" alongside of "if it all goes horribly wrong, what's the worst case scenario"? In this case, if you use a hanger extender, for instance, worst case might be that the original hanger bends or fails, rear mech goes into the rear wheel and you end up on the tarmac. It's a low risk but is it a risk you want to take? I wouldn't advise it ... but you might consider that kind of thing an acceptable chance to take.