Do you plan on video file transcoding with something like Plex?
If not, the Intel QuickSync is not needed.
As for the higher power usage from AMD, I would have thought the exact opposite in some cases. But, it is more of a case your mileage may vary.
Now on the disadvantages of TrueNAS with an AMD CPU, in general, less well tested. But, that also applies to the latest generation of Intel CPUs. Especially since Intel now has asymmetric core configurations, (aka E & P cores).
Their should be a lot of Intel based used server equipment available, that is quite suitable for TrueNAS. Probably very little used AMD server equipment, because many AMD servers have not yet run their end of life in a data center. And of course, not as many AMD servers are produced, (yet).
AMD server boards are tricky to find and may not be cheap enough for some people. AM4 socket tends to turn some people off since their is not 100% certainty that ECC memory will work. Plus, for real ECC memory support, the full SP3 socket for Epyc can cost an arm and leg. Their are some embedded Epyc boards that come with CPU soldered to the board that would be cheaper.
And, just having AMD does not excuse the board for having a Realtek network chip. Realtek chips tend to be less performant that Intel / Chelsio. So that can add a wrinkle in board selection.
All in all, AMD does not have low to mid-low server style chips that have wide options. The embedded Epyc seem to be all soldered to their boards. And yet the Ryzen are considered desktop chips, (though the Pro versions seem to support ECC memory). So, AMD is a mess at low to mid-low end server chips and boards.
