TL/DR Unless we get a defector high up in the Paizo hierarchy all answers will lack hard numbers for sales.
+1 to what @KRyan says but also you can do some sleuthing on your own.
Besides comparing usage stats at places like RPG SE, GitP, Rolld20, FG and scraping data from Amazon and so forth you can look at credits given in the masthead of official Paizo publications and compare that to their website over time and count the number of employees listed.
This can be confusing at first since freelance authors are often involved but you can also compare to the total number of publications per unit time. A falloff in the rate of actual product publication will be delayed about 6 months from the time they decide to scale back, if they do, so you're looking into the past with this method.
You can ask a local RPG retailer what message they're getting from their distributors. Are Pathfinder 2e items moving or stagnant? This will be a local to regional answer as well since we know there are pockets of secondary game popularity which don't reflect the sales of an entire product line.
Finally remember that the COVID-19 situation scrambles any answer. At least short term.
My personal opinion is that Pathfinder 2e is doing at least as well as 1e though groups playing 1e are sticking with that system more so than did D&D 4e players when 5e came out. My read on Pathfinder 1e players not moving to 2e yet 2e still doing good is because D&D 5e has grown the space for all RPGs and Pathfinder 2e is moving into that space. That is 2e is growing without transitioning all 1e players over because of RPG popularity in general. Further if you look at the link of all Pathfinder book publications you can see a hundred years or more of playing material there and there may be little incentive to move from 1e to 2e when your GM is sitting on a backlog of four decades of adventure potential.