It's not the processors which have been altered to not run Windows 7. It's Microsoft's decision to block all updates on anything other than Windows 10 on PC's with Intel Kaby Lake onwards, and AMD Zen (including Ryzen). There are some difficulties with installing Windows 7 on newest platforms (e.g. doesn't support USB 3/3.1 or NVME out of the box) but these aren't insurmountable with custom installation media. Some unofficial "hacks" are available, to get around the updates issue. But honestly, IMHO Windows 10 is a better OS anyway in most respects.
I can suggest a few things that may help with regard to system noise. For a start, a good air cooler is quieter than water cooling usually, and barely behind in performance for the really big air coolers. Large, good quality, low RPM fans are barely audible. I use a Thermalright Macho which is pretty good. Cryorig, Noctua and various others make some decent ones too.
The choice of case can have a big effect too. Some like the Nanoxia Deep Silence range, or the Fractal Design Define range are made to be as quiet as possible, with extensive sound deadening treatment inside. I have a Fractal Design R5 case, and I think it's pretty good on the whole.
Many newer video cards are semi passive (fans only operate under high loud) and for a pure DAW machine, you don't need much in the way of graphical power anyway - a passively cooled card or integrated graphics will do the job required.
Newer high efficiency PSU's often have a semi-passive fan mode too. Fully passively cooled PSU's are out there, but pretty expensive, and you will want at least a couple of quiet fans in the case just to get a modest airflow over the various heatsinks that need cooling.
Have to say I can't hear my current system over ambient background noise under normal circumstances, with the CPU fan running at 500-ish RPM.