Well, if your goal is to be 100% the same as what Microsoft offer, then sure no there's not. But that's letting them set the goalposts.

If you look at the features you actually need and are willing to explore different ways of doing things that are not exactly like M365 there's more options. France and Germany are also working on freeing themselves from M365.

This kinda thing sounds a lot like those RFPs that were specifically written so they could only be fulfilled by Microsoft because it was just a list of their feature tickboxes.