Thanks for the comprehensive reply. I asked questions for both scenarios because now it is possible to run Eudora Mail or Palm Desktop (PowerPC applications) in Intel-x86 Macs, installing such applications in a virtualized Mac OS X 10.6.8 Server in VMware Fusion.
Since that is possible, I thought that it could be also possible with macOS 11 Big Sur, virtualizing Intel x86, and inside it virtualizing PowerPC.