I'm currently using Niri and sure it's not a DE it does an excellent job of workspaces. each monitor has its own set of workspaces by default, no configuration needed.
I don't use Dank Material Shell or any of that but in all honesty if you wrap Niri in DMS or something like it then it actually becomes a near perfect DE. Even the Niri devs now suggest you install Niri with DMS.
just did this lastnight, went from Arch back to NixOS. was on Arch for like all of a week.