It's been a while, but thanks for the update! I can confirm the issue is solved, for my joysticks at least.
Please note these are proper arcade sticks and VERY recommended for this kind of game. Definitively not console-type gamepads, thumbsticks, D-pads and whatnot. Couple of examples (not the ones I'm using):
https://www.immortaljoysticks.co.uk/
https://monsterjoysticks.com/
More available. 😉
Thanks for the feedback! Glad to hear that the problem is solved :)
Never doubted you had proper joysticks: it's Windows that treats them as analogue devices! For clarity: the sticks of joysticks are digital devices and, from a software point of view, are equivalent to D-pads; however, at times, Windows reports them as analogue thumbsticks! In fact, the solution I adopted was to accept and handle also analogue input as if it were digital. In short, the game now features a workaround to a Windows issue.