They called it 77 because of the processor used. Using the AMD Ryzen 7 9135HS (which obviously doesn't exist) would've justified the HX77 name. At least that's how I see it.
I got a HX80G a couple of months ago, perfectly satisfied with it. Presumably this is due to the supply of 5800H slowly drying up. I hope they are still around with new products in 2-3 years when the upgrade cycle comes around.
With the same design and dimensions as the HX99G and HX80G, the new Minisforum HX77G mini PC is driven by the AMD Ryzen 7 7735HS processor with AMD Radeon RX 6600M graphics. The early bird prices start at US$639 for the barebone version, instead of US$799 MSRP, and go up to US$879 (instead of US$1,099) for the 64 GB/1 TB setup.