Question Building Home NAS...What PSU should I get?

[rohram04]

I've been looking at PSU's for an ITX Home NAS I'm building. I would like the PSU to be ideally under 80 dollars and at least 80 + bronze rated as well as semi-modular at the least due to the small form factor. Here are the system specs:

Ryzen 3 3200g
2 NAS WD RED 2tb hard drives
MSI Gaming plus AC Itx motherboard
8gb Patriot Viper Ram (2133 mhz)

I am planning to install unraid on it and it's going to be running 24/7. Here are some power supplies I've been looking at (Including rebates and sales they are all under 80 dollars currently):

be quiet! Pure Power 11 500W cm, BN628, Semi Modular, 80 Plus Gold, Power Supply
Corsair CX 450M 80 plus bronze semi modular
Corsair RMx Series 550x 80 Plus Gold Fully Modular

Because I'm running it 24/7 I'd like it to be relatively quiet and very reliable (Reliability is the most important factor). I'm just not sure if either of these are great quality PSU's and I just wanted other peoples opinion. Yes I know two are gold and one is bronze and that they are all big name "reliable" brands, that is not my question; My question is about the power supplies themselves. I also understand even 450w is more than sufficient for the system; they just don't have some models at/below that wattage.
Are there any other power supplies you could recommend for my use case if either of these aren't too great?

 

[jonnyguru]

If it's ITX, why not use an SFX case and an SFX PSU like Corsair SF450?

 

[rohram04]

My case (Rajintek metis plus), which is itx, supports an ATX PSU up to 160mm length and requires a bracket if I use a SFX PSU which is an extra 12 dollars. I don’t really want to dish out the extra 12, even if the price for the SF450 on newegg right now is very enticing. I understand the case may not fit a 160mm PSU comfortably, but I am willing to spend the time to cable manage and make it work. I also won't have a graphics card in the case as I am using the ryzen APU so it shouldn't be too bad. Also in terms of an small form factor case, the Rajintek Metis Plus is the smallest case I could find that could support 2 3.5inch hard drives that was also affordable.