It's worth noting that emulating x86 linux on M1 macs with qemu still sucks pretty bad. This was an important use case for me that I basically gave up on and got an EC2 instance, in addition to buying a couple more spare x86 machines.
Since the article at least seems to be saying the opposite, can you give some specifics about just how it sucks?
But the article is not saying the opposite. It praises a virtualization. About an emulation it says "while I’m not going to call it “fast,” it’s not utterly unusable either."
Virtualization of arm linux seems to work fine. Virtualization of x86 linux is very slow.