Most debit cards in Poland are standard Visa or Mastercard and definitely work online, sometimes you just need to activate them before the first payment for security reasons, but you're right that Blik seems to be getting more and more traction recently.
Yes, PayPass seems to be the go-to method in the physical world, even more so now (they have doubled the limit for non-PIN payments due to COVID-19 recently, so people don't use cash and don't touch the terminals as often), and Blik is winning on-line payments.
The cards reportedly do work on-line, but I have never bothered to activate them. I have a Revolut card now for the odd CC payments with US-based companies, but I hardly ever use it for this purpose. I don't get the security model of CC, to me it's like: "here are all the details you will ever need to charge me an arbitrary amount until the card expires in X years". Any other method I have ever used was 2FA: I had to authorize the transfer of funds from my account to the recipient by some means.