Congrats on your first Samsung. That's an easy question. You definately could have used your other chargers. So an 18W charger will charge at the full 18W on your S22. In fact, the lockscreen will actually say "fast charging" despite a different charger.
I use various chargers on my S22 Ultra. At work I have a meagre 10W charger and the lockscreen says "charging" only. I also have an 18W charger from my old Note 9 and the lockscreen says "fast charging". And when I plug in the 25W charger, the lockscreen says "super fast charging".
Also, the ports on your powerbank will work. Any charger that is the same or less wattage will work. And if you try and charge a higher than specified wattage charger, the phone will charge at its maximum rate-not the maximum rate of the charger. So for example, if I plug my 25W S22 Ultra charger into my old Note 9 (maximum 18W charging), the phone will charge at 18W only. Plug a 45W charger into a Galaxy S5 and the phone will charge at its usual 10W.