I was in the same situation, impatient to have a 2021 snapshot. Dirty hint: the .hk mirror still has the base part from 2020! But try it as a last option, the folks there are not so bandwidth fortunate. After installing the base, please switch /etc/installurl to something more suitable as distance and bandwidth.
Warning: I am not sure you will not finish with a Frankenstein system. I am not so good with compiler-linker stuff.
