2 out of 4 lights doesn't necessarily mean 50% or even roughly 50%. It means anywhere from 26-50%. According to Android Authority, wireless charging can range from 50-80% efficiency.

I did a rough math here. Your Pixel 7 Pro battery is 5,000 mAh which means it's about 18.5 Wh.

Your phone had gone from 84 to 92% which means about 1.5 Wh was charged by the wireless charger, which also means 300 mAh at 5V.

If we assume the charging efficiency was 50%, then to get 1.5 Wh on your phone, it used 600 mAh from the power bank. 600 mAh × 3.7V = 2.2 Wh.

A 10,000 mAh power bank will only have 7,400 mAh if we pull 5V on it.

In short, your power bank has roughly 29.7% remaining when you used it to charge your phone. That will still show as two lights.