Any ol’ fretless will do. They’re easier to make than a fretted instrument. Get one with lines and it will be easier to play if you like pitches etc. I do unlined but honestly with lines is easier to play and makes no difference in the sound.
Get the cheapest one you can find. If you like it then save up for a nice one. The all time cheapest bass is made by a guy named Gamma and he assembles them himself from Chinese-made kits and they’re a blast. If you change the pickups for nice ones then the Gamma basses sound great.
Or maybe a factory cheapo for like $150 or something. But definitely start cheap so you know whether you like it.
Oh and short scale is fine. Hell go all the way and get a fretless bass uke! 