There is no mirror redirection for add-ons, and these days we don't block any IP/CIDR ranges either, so if the device cannot connect to the repo the issue is likely something on your end.
FWIW, I have no issues downloading add-ons on an RPi5 here, and RPi4/5 use the ARMv8 add-on repo so that's correct.
Have you tried force-refreshing the repo in Kodi?