I built a fightstick the other week! Mostly for Street Fighter 6, though I have played some other 2D games including Hades and River City Girls with it as well.
Parts:
-Brook UFB Fusion board for compatibility with PS4/5, XBOX 360 and above, Switch, Wii U, PC and more
-Crown 309 Helpme K ST35 lever
-Qanba Gravity KS buttons for the top and Seimitsu standard for the sides
-Custom enclosure kit from Eternal Rival
I got an enclosure kit from here with a multiconsole PCB (brain for controller). I did research on what buttons and joystick I wanted and ordered them from focusattack and arcadeshock. I liked that I didn't have to solder everything and they gave me a useful guide for how to set everything up. I linked a build manual in another comment.
But you don't have to go that way! Depending on your patience and engineering skills you could make a controller out of nearly everything. You could get a cheap PCB from a working controller from a game system you like and a joystick and or some buttons and stick them in an Amazon box if you wanted!
Or, you could do what my buddy did and pick up a kool-aid covered broken street fighter 4 stick off the street, clean it out, and put a new board and joystick in it! It's up to youuu
Thanks for the reply. I’m going to go the route of reworking an existing controller and seeing if I can make a double joystick controller.
That's exciting! I hope you'll share your work!