I would call all the shops and ask specifically their QT process. Some LFS i visit simply keep the parasites at bay with low level copper and hyposalinity. Neither of which will erradicate the illness. Youll want to make sure their treating above 2ppm copper for a minimum of 14 days and other treatments for flukes and what not.
I don't know any shop that will do a full QT. Aquatic Collection in Hayward will treat all their fish but like all LFS, they run a shared sump. So the fish you see is being treated but that's not the equivalent of a full QT with only your fish in its own tank with nothing shared.
My QT is a 10 gal with a cheap powerhead from Amazon, a HOB filter and 2 PVC fittings from Lowes.
If anyone finds this thread in 2021, https://www.baybridgeaquarium.com/ does a full quarantine. Its owner is a microbiologist and they go way beyond prazipro+copper.
They sell gears at the same price as BRS and you can use "points" to buy fish.