There are basically no laptops with AMD GPUs. Why? I don't know. I think in the last months I've only seen one and I don't remember it as a laptop someone would buy.
I don’t know if they make them anymore but I highly recommend it.
Laptops with Nvidia dGPUs are available from many/most other manufacturers, as you said, so there is no real reason to buy them from them. Especially if they offer sub-par Linux experience.
Their can't keep up with the demand on the laptop market. How old are their Zen 4 processors? There are barely laptops with them. We had to wait months for a real use benchmark because it was impossible to get them.
Right now if I see and AMD GPU I wouldn't even know if it's new gen or from 3 years ago.
They are not on the market mobile market.