Profile avatar is “melting face” by Liz Bravo. CC BY-SA 4.0 | I am not affiliated with OpenMoji
I promote software freedom.
The responsiveness between a hard drive and an SSD is night and day. NVMe is even faster but not noticeable unless you move a hell of a lot of data around. A motherboard having at least 1 M.2 NVMe slot is common, so installing the OS on it is an option. Hard drives have more storage per price, but unless space is significant factor I suggest using SSDs (also quieter than a spinning disk!). More info on storage formats in this video
Recent generations of motherboards use DDR5 RAM, which were very expensive on release. I think the price has come down but I am not up to date this generation. You may be able to save money making a DDR4 system but you’ll be stuck on a less supported platform.
AMD had like ~10 years of bad/power hungry processors and Intel stagnated, re-releasing 4-core processors over and over. AMD made a big comeback with their Ryzen series becoming best bang for buck, then even over taking Intel. I think it’s pretty even now.
If you don’t intend to game or do certain compute workloads then you can avoid buying a GPU. Integrated CPUs have come quite far (still low end compared to a dedicated GPU). Crypto mining, Covid and now AI has made the GPUs market expensive and boring. Nvidia has more higher-end cards, mid range is way more expensive for both and low end sucks ass. On Linux AMD GPUs drivers come with the OS, but Nvidia you have to get their proprietary drivers (Linux gaming has come a long way).
The only PC fan manufacture that has not gone RGB at all is a Noctua (premium). Their fans are poop brown and beige or black for consumer, grey for industrial, but are great in terms of noise to cool performance. If noise is important then there’s videos of people comparing fans so you can pick a tone that is subjectively best.
I enjoyed the days of one color LEDS. Couldn’t beat a Tron blue or The Matrix green.