Were they slow? There's actually plenty of people
who can do that at a reasonable or even fast pace. Of course lots of people type reasonably quickly with two thumbs too (or in the case of this comment, a left thumb and right pointer finger).
I spent two years typing with just my forefingers, and can dk 80wpm with 99+ accuracy and I don’t look at the keyboard.
With two hands I’m still at 60-65 roughly and with worse accuracy but I’m sure it will come with time.
It’s why it’s taken me so long to try and adapt to touch typing. Too much muscle memory to rewire.