You certainly can log into a Windows machine without a microsoft account. It's actually still quite common in businesses that you log in with an account managed by your organization, although this is changing as more and more businesses migrate to MS Entra ID. This still isn't exactly a "microsoft account" but its similar.

You can also still log in with a completely local account as well. It takes a few extra minutes to set up but once configured it works fine.

The system is full of dark patterns and roadblocks that steer users towards an MS account, but you don't have to use one.