I know I'm replying after a month, but I just built a new PC. I switched from an i3 6100 to a Ryzen 3700x. I'm not sure what's going on with your setup, but the Affinity suite opens nearly instantaneously for me. I definitely don't think it's a Ryzen thing.
I'm still in the process of recovering, but I had some severe drive failures recently and am now on a fresh install of Windows 10 where it launches fairly quickly. I haven't timed it exactly, but it launches in around 8-10 seconds now. Slower than Photoshop, but not an eternity either.
Someone on the Serif forums suggested it may be due to the number of ICC profiles or fonts installed on the system, and since this is a clean install there would be less of them right now. I'll report back if I ever figure out what was causing it.
For now, I have decided not to reinstall Photoshop to force myself to learn the Affinity apps, as I'm not doing anything critical right now which requires it, but the workflow still seems to be a lot slower and there are many common functions that seem completely missing.
It really depends what you're doing with the app though; I'm sure that other people might not notice anything missing or prefer how Affinity does it.