Is 10G worth it for 8x8tb 5400rpm RAID6 w/ 2tb SSD cache? - eviltoast

I am investigating upgrading to a 10G network card in my TS-873 with 8x8tb (seagate 5400rpm shucked from easy stores) Raid 6 and a 2tb SSD cache with the goal of editing photos and videos directly from the NAS instead of managing files locally.

What I am unclear on is what the max speed I would be able to achieve on my system would be and whether I would even get close to saturating 10Gbe/5Gbe/2.5Gbe. Obviously prices for 2.5gbe equipment are way lower so if I can’t get faster than 2.5 I’d prefer not to waste the money on 10gbe equipment.