Supposedly K1-compatible stepper motors incompatible?

Hello community,
I hope the title of my post is halfway understandable. It’s about the fact that I wanted to change the pulleys of my K1 to those with 20 teeth. On the net you can find people who have done this and others who have tried but have not been able to get the pulleys off the motor shaft. That’s why I thought I’d just replace the whole motor when I find suitable ones with 20 pulleys. In fact, you can find a whole range of suppliers who offer compatible motors and even Creality itself lists this motor in the wiki: Stepper Motor Creality K1 with 20 Pulley

The strange thing about it is that it is not mentioned anywhere that the original K1 stepper comes with a 30 pulley and that you have to adapt the config for this supposedly compatible motor.

Furthermore, of course, I immediately noticed that the motor shaft is shorter than the one in my printer. In the installed state, it is mounted above the pulley in a ball bearing, which is obviously not possible here. But I thought, because this engine is called compatible everywhere, that the photo might not be correct. That’s why I took a chance and ordered two of these engines. Turns out: the photo corresponds exactly to what you get. I held the new motor next to the original, still installed ones and you can see directly that it doesn’t fit. The shaft is too short, the pulley sits too high on the shaft and the engine case is significantly shorter than that of the original. The latter is of course secondary if the engine otherwise meets the requirements.
Comparison original stepper with supposedly compatible stepper

My questions to you:

  1. Has someone possibly installed these motors somehow, e.g. by simply dispensing with the counter bearing above the pulley? I would find that creepy, because the original is also mounted on top of the K1C, but maybe this engine is designed for such a load from its internal bearings?

  2. Does anyone have a source for an actually compatible K1C engine whose shaft is the right length?

I have seen others replace K1 with 20 synchronous wheels, but he pulled down the original walking wheel with a horse, and then installed the 20-tooth synchronous wheel. In order to fix the synchronous wheel, he also needed to grind a plane on the shaft similar to the D shaft.