I find the DigiD app to be one of the most annoying implementations of 2FA out there. You have to unlock the app with a pin code, then enter an app-generated code on the site, then scan a QR with the app, and then grant permission to login to that site. If you compare that to 2FA for Office 365 for example, where you just have a push notification where you press a button to allow, then you can't help but think that s…
That's a bad comparison, as you're comparing a full authentication process against just one step: with Office 365 (and SMS verification for DigiD) you additionally need to provide a username and password, which you don't need to do with the app. I think the only part that can reasonably be simplified without compromising security is to use a push notification instead of having to scan the QR-code.
I hadn't even noticed that app login doesn't require username and password. With a password manager that doesn't add a lot of friction. Even when accounting for that extra step, I still find Office 365 and SMS verification much easier.