I have been a user of Mimiq for about 5 years now, and yes to use it you need either Avid Ultimate, or a perpetual license to use bin sharing.
The original poster did not mention shared projects, just using network drives, and you do not need anything special for Avid to simply see a network drive.
If i turn off Mimiq, i simply lose the ability to invoke bin locking when multiple users are on the same project.
I actually worked on a series two years ago at a facility with 3 suites, and a brand new (non Avid) shared storage system. I assumed we could do bin locking, but they didn’t have Ultimate, just basic Avid. This did not limit any of us from seeing the network storage however, we just had to be careful about which shows/bins we were all using.
The OP says they did turn on alldrives command. Sounds silly, but I would try that one more time, and make sure it worked, as that would be the most common reason to not see a network drive. If not that, then perhaps there is something odd in how they are being shared.