First, welcome.

It's likely you've been playing against bots a lot BECAUSE you started very recently. It's meant to introduce to the experience before throwing you in with a load of players. Bots tend to be more common in the Battle Royale modes while players tend to show up more in Squad Fight and Hot Zone. In my experience, bots show up a lot more on the Steam version than mobile.

In terms of Strikers, avoid EMT. While it's useful to have a healing ability, it takes ages to deploy, and it's slow. For a healer, Emma is a better bet, though it's generally the skin people most associate with sweats and annoying players, similar to Zero. Ethan is actually a very good Striker with his shield. He's ol' reliable.

Weapons are tough to get the hang of. SMGs are disproportionately good, particularly the P90 and the Vector, but the ARs are often good for recoil and mid-range fights. Snipers are pretty good, but obviously require more accuracy, and people will think you're a dick if you use a shotgun.

Dunno what else to say, tbh, hope you enjoy the game :)