Why Parallels 13 with Catalina so slow?

I used one stack(Parallels 13 + Windows 10) during 2 years on the same MB Pro.

"Maybe ask Parallels why"

I have no problems before with High Sierra, Mojave. I was very happy to work on MB Pro. Until that day when I installed updates Catalina. Guys it was oweful update I never faced before. It stacked my business. Also I had seeing a bug with progress bar few weeks, that you fixed in the last updates. Your updates last time very not stable. It looks like Alpha version with a lot of bugs. I chosen Mac because it was very fast and stable previously. Now I have 2 ways: downgrade my Pro to Mojave or buy Windows laptop. For me easier to buy new laptop. Unfortunately I bought Air two weeks ago for my wife as gift and completely forbid her install any updates. I lose a trust to Apple.

"Maybe you have not installed it correctly." Any changes until that "Catalina updates" day. I started Parallels, Windows and was very mad that I not able to work on my MB.

"Maybe you have not allocated enough memory to the VM." Any changes just Catalina update

"Maybe you are running a very resource intensive system in the VM." As usual the same image with the same resources.