> I wish someone would just tell me exactly what to buy.

I’ll bite. You can save a lot of money by buying used hardware. I recommend looking for old Dell OptiPlex towers on Facebook Marketplace or from local used computer stores. Lenovo ThinkCentres (e.g., m700 tiny) are also a great option if you prefer something with a smaller form factor.

I’d recommend disregarding advice from non-technical folks recommending brand new, expensive hardware, because it’s usually overkill.