I went through the comments briefly and didn't see anything about cases. I highly recommend spending some money on a good case with good cable management slots. It may not look important but it will make life so much easier. Fractal cases are good budget friendly ones. I usually prefer large bulky cases (I like ATX), to ensure good ventilation and easiness to assemble things. Having plenty of space to move around helps a lot while cleaning also.
Another thing, you will see a lot of articles about positive pressure or negative pressure fan arrangement and all. TBH, I really don't think that matters a lot. Just regular cleaning with a cheap rocket air blower will do. And more than 4 fans are not really needed. The gain is negligible. But ensure you have a good dedicated fan/water cooling for CPU cooling. I recommend Noctua for air cooling.
Oh regarding backing up your data, make sure you plug in your SSD once in a while, to avoid charge depletion. Nowadays the claim is SSDs have better retention and you don't need to keep it active, but I'm not really sure.