Yes and yes. I assembled it in August - it's working great! Very satisfied.

Yes, it fits. But you have to load a new BIOS version onto the motherboard so that it recognises the computer. I have separate cooling via the tower.

As far as I can tell, it doesn't have a heat sink for the SSD. It runs smoothly with AMD Ryzen 7 5700G.

Since the AMD Ryzen 7 5800X is an am4 processor, it should fit without any problems.

I personally have 2 ssd m2 installed on the board and the covers are also the heat sinks.

Yes, it fits, I have the Ryzen 7 5800X3D on it and it runs great! And it has heat sinks. It has two M.2 banks if that's what you mean by SSD.