So the QNAP has 10 gbps on it, eh? Have you also setup a 10 Gbps network at home? I'm thinking that will be my 2020 project.
At home I just have a Akitio Node thunderbolt enclosure with a dual 10Gb Nic. so NAS to Nic to iMac.
The 1Gb port connects to the rest of the network.
The NAS is a TVS-951X and I upgraded to 16GB of RAM myself.
https://www.qnap.com/en-us/product/tvs-951x
(If I am not in a hurry I will typically watch the Amazon used section for better deals. Example on this NAS, I saved $120 and the package wasn't even opened, there was just a damaged corner of the packaging so it was listed used/like new, and I have a 45day return window with Amazon so I will use this frequently to save some cash)
So I get 10Gb connection on one machine. I just haven't had the want to purchase any more 10Gb equipment as I'm the only one using it at the moment at that speed.
The Akitio was leftover from a previous eGPU setup and I had extra dual port 10Gb NIC's at work from a build-out a little over a year ago.
Doing this, was less expensive than most Thunderbolt 10Gb solutions. The NIC was bought on ebay for around $35 shipped and it came with a 10Gb fiber transceiver and a 10Gb copper tranceiver.
I already had the other parts to make it.
So my home solution is a :
Thunderbolt 3 to Thunderbolt 2 adapter
Thunderbolt 2 cable (from iMac to Akitio Node)
Akitio Node
Solarflare SFN5122F Dual port 10Gb NIC (inside the node) (the old mac drivers still work on the newest os)
10Gb fiber to copper transceiver
CAT6 from the NIC to the NAS.
Not the most elegant solution but it works well.
At work I have a UniFi 16 port 10Gb Switch and all of the servers and NAS devices connect directly to this, then 10Gb fiber runs out of it to the dual UniFi 48 port switches. So more of a proper setup there.