There are two sets of mirrors that you may update: Arch (as we are using Arch mirrors directly) and EndeavourOS.
You can update Arch mirrors on the command line (too) with any of the following programs:
reflector-simple
reflector
rate-mirrors
And EndeavourOS mirrors with
eos-rankmirrors
rate-mirrors
Typically the Arch mirrors may need to be ranked with any the related tools above. The EndeavourOS mirrors are often OK as-is, but maybe that’s not the case in all scenarios.
For more details, look at the help (e.g. reflector --help) option of the apps (if available) or use eos-apps-info program to see more.