Seems to me there are a few core issues here that might need sorting.
A: do you really need that particular dealer to define your home listening environment? (Or is the tail wagging the dog to some extent?)
B: as good as the Rega P10 may be, it’s limiting
C: the Kuzmas are expensive but they deliver a lot of value for the money.
I’ve had a ‘crush’ on the P10 for a while, but I can’t live with a locked-in tonearm, especially at that price point. I’m too much of a tinkerer.
I recently bought a Kuzma Stabi R after deciding it was time to move on from my modded VPI Franken-table. I already own two isolation platforms that can work well, so that was an extra synergy. I guess my point is, if you can stretch your budget upwards, you might want to look higher up the Kuzma chain (the R) and think about how to involve your dealer on the ancillaries (as you mentioned).