Hey, congrats on getting started Unraid, I'm waiting for my own components to come later this week after watching many hours of tutorials and build guides online. These are the parts I ordered which I think falls into your budget (assuming the hard drives were not included).
Fractal Design Node 804, mostly because it has 8 drive bays and is fairly compact.
ASRock X570M PRO4 AM4 AMD X570, it has 8 SATA ports along with 2 m.2 slots.
AMD RYZEN 7 3700X, provides 16 threads, should be plenty for most uses.
CORSAIR Vengeance LPX 64GB, this should provide plenty of head room for now while making it easy to increase the total system to 128GB in the future.
Crucial MX500 M.2 2280 1TB, I'm going to use two of these as cache drives along with keeping apps on them.
WD Blue SN550, since the motherboard only supports a single SATA M.2 (and because PCIe is faster) going with these SSDs will work.
PNY Quadro P2000, I'll be using this for hardware transcoding with Plex (not sure if Emby has something similar) and will be overkill for now but wanted to just set it and forget it.
If you don't have a UPS already, then this one would likely work for you, you can also setup your Unraid server to automatically shutdown with it.
