You did a good decision. With this game not only can you bite the bullet, you can swallow it as well
For controls you always hit the xbox controller icon, as you already know that. There are 3 strikes in the general menu:
Fire 1 aka normal strike. it's used as a defensive counter shot. Very good and not hyper sensitive. maximum speed 119km/h
Fire 2 aka slice. defensive slice mostly. but with good height you can make it travel really fast, so it becomes offensive. Safest shot there is. max i've seen 110km/h. mostly 102km/h
Fire 1-2 aka acceleration strike. Now this is real offensive shot. One of the sensitive shots. There is also shoulder height acceleration like djokovic in real life. Fast as 160km/h. but you need very good height and precise preparation.
Technically speaking you can play all 9 strikes available with just 2(!) buttons. One for fire 1 another for fire 2. If you hit both of them at the same it becomes fire 1-2.
But really do like @C4iLL said. Hit the remap strikes and change all those 9 buttons. For your safety move those 2 lobs to some button that you don't use much. You don't accidentally lob then. Short acceleration and short strike needs a lot of time so move them to separate button as well. And then use 3-4 actively for playing the game.
Then just reconfigure and hit the practice arena. See what you're comfortable with. I've no idea what you do if you're playing with controller.