But a fellow Linux user named Dolphin Oracle shared these useful tricks on MX forums:
sudo mkfs.ext4 -E root_owner=$UID:$GID /dev/sdXY
where /dev/sdXY should be replaced with /dev/designation_of_partition.
The command above will set as user whoever issued the sudo command. You will still need to mount the device as root, but you may use its files as a regular user.
If you want something a bit different, he also shared this one:
mkfs.ext4 -E root_owner=uid:gid /dev/sdaX
where uid is the user id of whoever you want to be owner (the user created at install will have a UID of 1000).
where gid is the group id of whoever you want to be owner (the user-group created at install will have a GID of 1000).
If you want to mount the devices as a regular user instead of root, you'll have to do this:
paste the contents below into a file called /etc/polkit-1/localauthority/50-local.d/50-udisks.pkla
Reboot and then you should be able to mount the devices as a regular user.