I am new to raspberry pi and have picked up a pi4 which i intend to use for small projects to learn how to use them.

I have a pi1b from years ago but only spun it up for the first time a few weeks ago to serve as a pihole and a jump box to get inside my network with tailscale for various reason.

Its not powerful enough for anything beyond that that i need

I want to start with a NAS for a media server and have read about HATs you can use but im getting confused about what is better between SATA HATs and m.2 hats or just using USB with power injection for HDDs.

I intended to set up RAID 5 with 4 SSDs but am appy to go a different route. I just want something basic but not too slow and not too bulky.

The pi is a pi4b 8gb model.

I did search before asking here and have watched a number of youtube videos but couldn’t find what i needed. And overall found the videos to be confusing as they all recommend different stuff and dont really get into detail about why one is better than the other.

Thanks in advance.