Yes, you need a dedicated server. Or a dedicated shared storage product, like one of the countless ones you see advertised right here on Creative Cow.
Thunderbolt networking does not work. You should get a nice simple 10G system, and you will be fine.
There is one for every budget, including REALLY inexpensive ones. Getting 40 TB today is easy with 6TB and 8TB drives. 8 x 8TB = 64 TB, and 8 x 6TB = 48 TB, so you will have no issue doing exactly what you want.
Let me assure you that if you try to use your main Mac Pro as an editing or AE station AND as the server, nothing will work.
Let me know if you need more info.
Bob Zelin
Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com