compared to full-VMs-pretending-to-be-containers everything is fast.

it seems like everybody here is using Macs for development to the point that if you don't say you aren't, you are assumed to be on a mac. Windows with WSL2 is actually pleasant to use, I can recommend trying it out. while WSL2 is a VM technically, the level of integration makes it basically native (if you use the VM disk for your workspace, which you should.)

It's not the COW filesystem that is slow, it's bind mounting the host filesystem into the VM. This ends up using something like 9p or sshfs.