But your bank needs to be in Germany, Belgium, France, or "all of Europe". When you select the latter, my Dutch bank isn't shown

I also have a shared account in Germany, but paying with that doesn't work either. I need to make a Google account and buy a compatible phone to download their software

This is advertised as a replacement for iDeal, a Dutch system created by a collaboration of banks as far as I know. It worked very simple: (1) click pay, (2) select your bank, (3) you're redirected to your bank's website, (4) you use whatever you would normally use for online banking (chip+pin with an authenticator, the mobile app, whatever your bank offers), (5) the website redirects you back to the merchant