It’s been a long time, but having dealt with Adyen a few years ago my take away was they are way more punishing regarding your implementation (we had calls randomly fail, users not getting redirected, notifications out of order etc.), with more options but also more rope to hang yourself.

Those are all use cases we needed to cover either way and we did, but errors were part of the routine more than exceptional events. In comparison Stripe was way smoother and documentation/support a lot easier to grasp.