So I purchased a rack mount that came with a SATA SSD PCB. I want to get away from using the micro SD card and I heard SSDs compliment the pi well but I’m not sure how to go about doing it, do I just flash the ssd like I would a micro SD? If anyone could please give me some advice on the best way to do this I’d be grateful!
Slapping a SSD onto the Raspberry Pi is like putting glitter on a pimple. For one, I don't think there's TRIM support for the SSD, and that will trash the SSD. Secondly, the SSD is way, way overkill for the capabilities of a RPi, so it's really a wasteful decision. Do you have an actual issue to resolve, or it's just that you now have the SATA interface available and have the itch to use it just because it's there?
If the microSD performance is inadequate, perhaps more importantly you should ask yourself why would you stick with a Raspberry Pi to begin with. When the RPi was like 30$, it was simply unbeatable in performance over price. But with the prices exploding in the past few years, there are other SBCs with ARM processors that are within the same approximate cost with a RPi, but offering a lot more performance and benefits. For example, the Odroid N2+ has a CPU that significantly outperforms the one in RPi 4, faster RAM, better connectivity, faster display output, AND has a removable eMMC storage that's significantly faster than a microSD.
TRIM on Pi is possible if the USB controller supports it. Even without TRIM the USB SSD is ALWAYS having longer life and running a lot faster than SD card, and not to mention sometimes we need much bigger storage only (e.g. previously I used my Pi4B as torrent client alongside with PiHole/UPS management, plugging a SSD to it just fits the purpose)
And not everyone is buying Pi at high price, for example I have 3 x Pi4B purchased long time ago which were cheap.