There are plans for 64-bit kernelland with 32-bit userland, which will notably permit to efficiently make use of more than 2 GiB memory and provide 4 GiB userland addressing space.

A 64-bit GNU/Hurd is also available, progress is tracked on 64-bit port! As of April 2025, the Debian hurd-amd64 port works just like the hurd-i386, except for some bugs, namely swapping issues with rumpdisk and the hurd-console fails to start, which means that you cannot use X.

We plan on supporting both a 32-bit and 64-bit Debian GNU/Hurd, only not both at the same time.
However, there is no plan to fix the year 2038 concern on a 32-bit system.

That being said, you can always run a 32-bit version on a 64-bit machine, it just works, processes are just limited to a couple GiB available memory.