Custom components are more likely to be poorly tested, and to fail. The drivers are more likely to be unstable.
Off the shelf components are far less likely to have defects in them, far more heavily tested, and to be designed by people who specialize in designing that one thing, with far better documentation available.
Unless of course you’re buying them used off eBay for 10 bucks.
Personally, I would have gone with a Logitech G56 HOTAS set up. You don’t necessarily need all those buttons, but the drivers are designed to allow you to easily customize them (including with custom curves.) and the stick would give you 3 axis control (twist for use,)