> do you mean there will be no QEMU emulator dropdowns in speed
> even if it will use the host's CPU? I mean, it still will be slower than
> native IMHO. [...] EDIT: I read that KVM can run a guest OS at 95-98%
> of the host’s native performance

Running a guest OS in QEMU KVM-PR mode makes the user mode instructions run directly on the host CPU and the supervisor/privileged mode instructions run emulated. Thus, the overall performance depends on the distribution of the executed instructions, i.e. the less supervisor/privileged instructions the better the performance.

> QEMU should be run from something, so it will mean MacOS
> probably necessary too.

I'm not sure that current/future QEMU versions can run on 11½ years old MacOS.

> it probably lucks audio driver and RadeonR92xx driver (with all compositing
> things working) [...]? Or there already some audio/video drivers support being done?

Audio: QEMU can emulate Ensoniq AudioPCI ES1370 chipset (deployed on Sound Blaster PCI128 card), which OS4 has drivers for. So if QEMU can't emulate the Pegasos II onboard audio, you can always insert a virtual SB128 sound card into the virtual Pegasos II.
Graphics: Correct, no Radeon or compositing etc. yet. However, I think it should be possible to insert a virtual SM501/SM502 graphics card into the virtual Pegasos II (as had to be done for running MorphOS on QEMU PowerMac3,1/mac99 emulation before the Rage 128 Pro emulation emerged).