After some research I found that on other distros, udisksctl has suid root. Mine didn’t have it so I added it in the same manner as described in the ntfs 3g faq
[N] ~ ❯❯❯ ls -l $(which udisksctl)
-rwxr-xr-x. 1 root root 62368 Mar 3 16:41 /usr/bin/udisksctl*
[I] ~ ❯❯❯ sudo groupadd udisksmount
[I] ~ ❯❯❯ sudo chown root:udisksmount $(which udisksctl)
[I] ~ ❯❯❯ sudo chmod 4750 $(which udisksctl)
[I] ~ ❯❯❯ sudo usermod -aG udisksmount nox
[I] ~ ❯❯❯ ls -l $(which udisksctl)
-rwsr-x---. 1 root udisksmount 62368 Mar 3 16:41 /usr/bin/udisksctl*
After which I could mount my partition using udisksctl.
[I] ~ ❯❯❯ udisksctl mount -b /dev/sdb4 /mnt/windows/
Mounted /dev/sdb4 at /mnt/windows
Using my graphical file explorer, the password still gets asked.
I will mark this thread as solved since I can mount ntfs partitions as an unprivileged user.
Upon hitting the “details” button when I get asked for authentification, I can see that the x-udisks-auth option is specified in my fstab (even if I didn’t!). This is the problem.
You can follow my new thread in the udisks project github issues