We were also skeptical, but bought a used Puky balance bike [0] for our daughter when she was 1,5. It cost 20 EUR and basically had everything a normal bike has (brakes, added reflectors, bell) and she was able to use it for longer distances (2 km to daycare) very quickly and safely. This was a huge benefit for us, as walking this distance was usually an endless litany of "don't wanna walk, carry me please, take me on your shoulders please, etc", and a 2 year also doesn't really like sitting in a stroller anymore.
When she was 4, we bought her a regular bike. The "learning process" went like this: I told her "it's like your old bike, but with pedals to drive faster". She sat on it, used it like a balance bike for 3 rounds in our driveway, and then started to test the pedals. After literally 5 minutes, I went for a drive with her through our neighborhood.
We were completely flabbergasted. It took both me and my wife 2 long Sunday afternoons with our dads in a large parking space to learn to ride a bike. We both started with training wheels when we were 2.
[0] https://www.gigasport.de/puky-laufrad-12-lr-1l-br-pink-72928...