I find that it takes a ridiculously long time to learn how to ride a bike. You think they will have learned by filling the whole progress wheel in one go, but no! They don't. You still have to have them keep practicing endlessly. And it is very glitchy, especially if you are near a building - they will cycle vertically up and down platforms, steps, through walls, hedges etc.
If you want someone to teach them (slightly quicker result, in theory) I find it best to get both the adult and the child with the bike into an open space and then get the child to ask if they will help them. Even then, sometimes the adult will still just wander off to do something else.
And then all of a sudden, with no real indication of why, the child will suddenly be able to ride. I have no idea how many times you have to go around that progress wheel to get there but it feels like it's at least three. IRL we taught our kids how to ride a bike in less than two minutes - just hold the saddle and run with them and let go when you can no longer keep up - hey presto, they can ride a bike!