You don't say what model your MBP is but I have the 13" 2020. I will be calling Apple tomorrow as I have the exact same issue. I already have a case number from a previous call. I open it up from letting it sleep and .... no keyboard or trackpad. I get the popup telling me it is looking for a keyboard but usually it finds the keyboard and the trackpad starts working a few seconds later. Occasionally they don't and I have to hold down the power button to restart it.
The Apple tech recommended a whole lot of things to try. Here is what they recommended that has not worked:
Reset SMC and PRAM - multiple times
Have done a complete reinstall of Catalina
My idea: Shut off the new battery health feature - worth a shot?
My idea: In Energy Saver unchecked everything but Power Nap - Just an thought.
Because I was at home when I called, where my internet is slow, we could not run a hardware test but I am sure we will on Monday. Regardless, my conclusion is there is a problem with the hardware. Prior to this 2020, I had a 2020 13" 17 that I had sent back. I had decided 16GB would not handle my video work and I wanted a 32GB model. The one I sent back never had this issue and ran just fine. This is hardware and it will be going back.
Lisa