Best thing you can do is spend the money and go rent and shoot different guns at the range. A lot f indoor ranges have a good variety to choose from. In semi autos you need to figure out what type of system you like. DA/SA. Striker fired DA or a SA. I have all styles and all fit a different need and shooting style. As for caliber you need to figure out what you want to use it for. For paper punching and shooting a lot of targets 22 and then 9mm works well. For defense 40sw and 45acp. There was s a lot of choices out there. For revolvers for competition I shot 44 magnum with downloaded ammo that made it a lot softer to shoot while maintaining performance and volocity. 357magnum is a good cartridge and you can use 38 speacials in it to keep the cost down for paper punching. I also have some in 45 long colt and 32.
And as always 22s are just flat out fun to shoot and cheap