Please build two machines - one for gaming and another low power one for nas. It doesn't make sense to keep your gaming rig turned on 24/7 downloading stuff when the same can be achieved using a much lower power optimized machine.
Personally I use a b450 board with a 3200g and an LSI HBA card for the storage pc with 6x 10tb HDDs in raidz2. It's more than enough for everything. This box runs linux. Do note the LSI HBAs don't work properly in any modern windows version.
I did see some NAS oriented motherboard + mini ITX case etc.. but they seem to be too complicated for me.. atleast for now.
I use my laptop 24x7.. and IIRC , my current Sager 970M GPU laptop has been literally running non-stop for 3 years or so now.
I am planning to run my gaming system also 24x7 ..
Only very recently i have been putting the laptop on sleep at night..
Can you suggest a HDD less NAS oriented PC config ?I do prefer a mini ITX case.. i can hide away in a cupboard or something.