You can’t run docker normally on ChromeOS you can run it on some chromebooks that support dual booting with something like GalliumOS, or rooting the machine and running your Linux distro in a container/chroot.

Unless you are severely strapped for cash and can’t find the same low end chromebook hardware in a low end windows form factor that can be simply reinstalled over there is absolutely no reason to even consider using a chromebook for anything other than it was intended unless you are rooting it for a hobby.

People abuse the fact that you can sometimes find them for sub $200 for $300-400 worth of hardware but it’s a hack on top of a hack to make it run anything.