Help me with my DIY project (United States USA)

Hi there. I have some decent experience with Linux and building computers, and I want to do a DIY project to run Volumio on dedicated low power hardware here in the United States.

I need help with four things at the moment… and when I get solutions, I’ll post them here, and as I make progress, I’ll post it here.

First, I know I want a HAT style DAC i.e. I want something that will fit on top of a Raspberry Pi, so the result is reliable, compact and reasonably high quality. Recommendations?

Second, I am having trouble identifying companies to purchase parts from. Initially I thought I wanted to go with HiFiBerry for the DAC but pricing and availability seems to be all over the map. I have some preference for a US based supplier, and it would be ideal to buy everything from one company.

Third, any recommendations for a solid basic case? I don’t need remote control, or displays, or anything… I am planning on controlling the device exclusively from phones, tablets, computers.

Fourth, and I guess this wraps the whole thing up in one obvious bow… anyone want to take a stab at a shopping list of what I need to buy? It would be supremely annoying to get a shipment here and find that I needed a SD card, or an adapter to read an SD card, or a power supply…

I did do some searches online and read through a few DIY projects here too, but many of them don’t really spell out what is actually needed, and many of them are a lot more ambitious than my needs, and many of them are folks that live in other countries… I’m hoping someone on this forum lives in the USA and recently built something like I describe, and I can crib from their notes.

Thanks in advance!