So I have installed an Intel X540-T2 10Gbe card in my desktop PC and it connects to my QNAP 453Be (with 4 x Ironwolf 14TB drives and a 10Gbe PCI card installed). I was configuring Jumbo Frames but can't match the 2 devices. The nic offers 9000 MTU but the NAS offers 9014 MTU. Is that a match? Are they supposed to be exactly the same numbers? Doesn't seem to be an option to directly enter an umber in either case - just select from the drop-down box. File transfers work OK - 235MB/sec from a single HD and 280MB/sec from an SSD. OK for single drives and I hope to get better when my second QNAP NAS is wired into the 10Gbe network.
I have the same situation with my Synologies and home computer.
You should not mix jumbo frames and standard frames if you are able to avoid it. If you google it several of the results will discuss the mixing of framed (I can't put URLs in my posts so therefore no links).
I have solved it by having a Mikrotik 5 SFP+ port switch where I only connect my computer and 2 NAS's and having a normal 1 Gbps connection from the computer (and NAS's) to the network for internet access (only FW updates for the NAS's).
It seems that you are going to set up a cable between you computer and NAS without any switch - so do the configuration as you have done with jumbo frames and it will work great for you (based on my experience that it does work for me..
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Also consider that when testing your computer must have a faster disk than your NAS if you want the most accurate transfer speed test.
If your computers disks are limited to 280 MB/sec then it does not matter what speeds you NAS is able to provide.
The reason I'm bringing this up is that you SSD speed should have been higher from the NAS i you are connected on 10 Gbe NICs.
Have you tested to run any of the disk speed test programs that are out there to see if the speeds to the SSD on the NAS will get higher (I can't recommend any program that works good with speed test to a network share).