They are very popular and make quite good products, but as you noticed it can be tricky to find them in stock.
Besides stuff like this switch they've also produced pretty cool little micro-switches you can PoE and run as WLAN hotspots, e.g. to distance your mobile user device from some network you don't really trust, or more or less maliciously bridge a cable network through a wall because your access to the building is limited.
I did some digging to find the switching chip: Marvell 98DX7335
Seems confirmed here: https://cdn.mikrotik.com/web-assets/product_files/CRS812-8DS...
And here: https://cdn.mikrotik.com/web-assets/product_files/CRS812-8DS...
From Marvell's specs: https://www.marvell.com/content/dam/marvell/en/public-collat... Again, those are some wild numbers if I have the correct model. Normally, Mikrotik includes switching bandwidth in their own specs, but not in this case.