When you say "Docker Engine" that suggests other parts of Docker are licensed differently (I haven't looked into it). I'd say you have to compare the whole ecosystem and not just a single component either way.

I said "Docker Engine" specifically because it is "Docker Engine" that is the counterpart of Podman, and therefore it is the only component that matters. The discussion here is "Docker" vs "Podman," but "Docker Engine" is what we really mean when saying "Docker."

Docker Desktop has a much more restrictive license. Unfortunately, on MacOS and Windows, the "Docker Desktop" product is often referred to as simply "Docker".

FWIW, Podman has an open source alternative to Docker Desktop as well.