Warning the new Parallels 16 Desktop Standard is EXTREMELY SLOW on MacBook Pro running Mojave. I did not want to pay for a subscription. It seems Parallels purposely made the standard non-subscription version slow. My older Parallels 14 which I tested for Parallels was fast and efficient. Since they limited my complimentary edition (since I was an official tester) to one year, I thought that I would get the same product by upgrading to Parallels 16. When I tried to run Win7 and then later Win10 on it they both HUNG for 5 to 10 MINUTES to open a program like VS2019. So it seems Parallels purposely crippled the Standard version to force users into their subscription.
So based on an anecdotal sample size of exactly one Mac -- yours -- you've not only determined whatever performance issues you're experiencing can only be attributable to deliberate performance handicapping by the vendor, you feel strongly enough to broadcast this publicly as a warning to others. Have you tested this on different hardware? More importantly, have you tested v14, v15, or v16's Pro versions against Standard to see if there's, you know, an actual difference? I've been using Parallels since v3 and have been a Pro subscriber since v14. I'm an IT manager and I admin multiple clients that use both the Standard and Pro versions. This is the first time I've even heard of such an accusation.