i much prefer intel for these things, idk why ive just seen it work better
mbd is overclockable although cpu is not, this is because this board has alot of SATA ports for more drives later on as you need them, also allows upgrading later on
this drive is one of the best NAS drives on the market, if you want something somewhat cheaper you can go with Ironwolf Non Pro, or WD Red Plus (Dont get WD red non plus)
your current drive is ok, i just upgraded to 500gb for more headroom for your OS
the case you chose doesnt have great airflow, either get the airflow version for a little more or the one i recommended
Your PSU was A tier on PSU cultists list although a little pricier than this one which is also A tier and higher wattage, this will definitally allow you to upgrade with a GPU or more drives later down the line.
may want 32gb later aswell, although as long as you have dual channel you should be fine for now