Are general hardware recommendations around that I did not find? There are so many options that I am lost.
I’m looking for the best hardware for my data host. It should be capable of hosting 2 TB of nvme storage and consuming as little wattage as possible. It should be powerful enough to run syncthing without problems.
I’ve got an Odroid M1S, but I can’t get it to work with dietpi, so I’m willing to purchase an alternative. But I don’t know which one is best.
I like this guys take on this new little NVME NAS thingy (not a cheap SBC though)
Could get one of those NVME hats for SBC’s
Lately I was also looking for cheap device to set up a NAS,and I found this:
https://de.gmktec.com/products/gmktec-nucbox-g3-plus-intel%C2%AE-twin-lake-n150?variant=50663568605368
It’s not ARM, but has just a TDP of 6W and it will run circles against e.g. RPi 5.
There is a spare M.2 slot (only PCIe 3.0 upto 2 TB, but that’s enough for me) and it’s pretty cheap, 130€ for 8GB/256,GB version.
Comes also with WiFi 6 and 2,5Gbit Ethernet. 
But it has no GPIO, which you probably don’t need for a NAS and it’s not as cheap as the odroid.
Edit:
OK I see the M1S is half the price, but has only PCIe 2.1 x1 (which should result in ~400MB/s, which should be enough) and “only” 1Gbit Ethernet (which is probably also enough 
) and has a typical power draw of 3.7W.
Idle power is the nucbox is around 12W (I got confused by the TDP, which is about heat and not power consumption) and under load it’s easily doubled, so I guess the M1S is the better deal here and I think the limiting factor will be the Ethernet speed. Even with 2.5Gbit you are capped at around 250mb/s.
and comes without SSD 
Fun fact: the GMKtec NucBox G3 Barebone (without RAM and SSD) is around 120 €
while the system with 8GB RAM and 256 GB SSD is just 9 € in addition (129 €) 