Have you looked at the laptop market lately? AMD has had quite a few design wins. Brands like Lenovo (including the Thinkpad, flex, and legion), HP (pavilion), Dell (including inspiron, gaming, and Alienware lines), Asus (Studiobooks, zenbooks, TUF, and ROG), Acer Aspire, and MSI, and the Microsoft Surface.

I wouldn't call all of those "niche". AMD has made a surprisingly quick move from the bargain basement laptops to the Thinkpad and Microsoft Surface lines in a single generation.

The nice thing is the new chips are pin compatible, so every current design win should move over to the new chips quickly. In fact half of the Ryzen 5000 laptop chips are renamed and slightly tweaked zen 2 chips from the previous gen. Based on the number of leaks, benchmarks, photos, etc it seems like the channel might well be full.

So I'm comparing laptops available in Nov (although people I know couldn't get theirs till Dec) to laptops I expect to be available in Feb, but that's speculative of course. Even the previous gen (zen 2) APUs are getting similar write ups to the M1. Things like benchmarking against the I9-9980KH and i7-1075H and winning. The zen3 is quite a bump vs the zen2 so I'm optimistic it will go well.

I'm hoping to get a few, maybe a mac mini like widget and another for a NAS. I don't expect them to crush a M1, but to be reasonably competitive, and while I contributed to the patreon to get linux on the M1, I expect the Zen 3 chips to have much better linux support.