I'm looking into getting one of those too and from what I've seen, its basically only relevant to get the more expensive Micro 2 if you're planning to mess with overclocking a lot. The price increase comes from increased VRM count and some other stuff and improvements I can't think of my head rn. Other than that, both ot them feature pretty much everything you would want from a high end overclocking mainboard. Can't tell you much about store availability tho since I'm from Europe and the store doesn't even work here lol

Download the manuals and images, study the specs and decide which one better fits your needs.  Can you live without USB-C?  Do you need the extra VRM?  PCI slots differ too.  I am not sure that the marketing people who call it an evolution of the mATX actually looked at the two boards.
 
I have a mATX 2 with 4 x 8GB, an Intel 760P NVME, an I9-10920X and a 2070 Super Black.  With only setting CPU to auto and enabling XMP, it runs all cores at 4.8GHz, cooled by a Cooler Master 212 (black;)
 
It is a mighty cruncher of data and mighty fine platform for Space Engineers.
Bonus: No RGB!