> My thought was why use UTM? Most of this can be achieved with qemu alone
Afaik UTM uses Qemu under the hood, but provides a nice UI on top for the basic use cases. It also has a library of prepared images, so that your VM is a few clicks away from intention to have one.
It can also modify the VM, resize storage after creation etc.
Of course all of it can be done with QEMU alone, but this makes it easier to deal with than remembering tons of QEMU command line arguments.
Thanks to this website, I gave up chasing an elusive target of squeezing 1gbps over wifi on any of my devices - it explains really well what is going on and why I was banging my head against the wall trying to make it work.
A useful trick to explain you current wifi speed on Mac is to alt-click on the wifi icon - it immediately gives tons of useful connection properties that you can make sense of after reading this page.
One more thing that doesn't seem to be mentioned that may decrease the wifi speed - is installing an open-source firmware like OpenWrt on your router. While it gives a ton of cool benefits, it is totally possible the drivers etc that come with it will be worse than stock firmware.
Then spin up the dB using that image instead of an empty one for every test run.
This implies starting the DB through docker is faster than what you're doing now of course.