I run a CSL Elite PS4, Pedals plugged into wheelbase and a separate USB shifter mapped via Joy2Key to 1,2,3,4,5,6 keys for H-pattern and U and J keys for sequential (both stick and paddles.) In paddle and h-pattern cars this works great; but recently the stick-sequential does not work, e.g in Caterhams and F3, and the car only shifts with the paddles. It is like any sequential car ignores the user-set Button Assignments for shifting and only looks at the wheelbase paddles.
Just to add to this in case anyone searches for it in future. I had an issue with Xpadder, which does a similar thing to Joy2key, where AMS2 wouldn't accept any keyboard inputs from my controllers. Solved by running Xpadder as administrator.