I’ve used Pyodex, i keep 2-3 lbs, I don’t use it often. The key to getting it to work in a flintlock is mix in a very small amount of 4f, for every 500 grams I use a 1/4 table spoon of 4f and evenly distribute, I’m not a fan of mixing powders but it works just fine. (Same with with Triple 7).
As far as it being more corrosive than BP, there’s more additives to pyrodex which can make a gun lock or bore much more dirty and it attracts moisture and ionized particles. That’s without saying if you’re not good a cleaning your guns, and use pyrodex you’ll eventually get pitting and corrosion. If you clean your guns good and regularly, you’re gun will be fine, however. If you’re only using BP and don’t clean your guns well or often, you’ll find its almost equally as corrosive.
A few months back I picked up a Charleville 1766 by Navy arms on auction for my regiment, the pan had to be cleaned and polished and then I spot welded some pits, I suspect because Pyrodex was used and the pan was not cleaned much ever or just wiped down, soap and water must be used and then lubricant.