I would personally stay away from any of these science projects, including Hackintoshes, home-brew custom PCs, Linux, etc.
If you are a serious Resolve-based business, making a living out of grading day in and day out, stick with either a Mac Pro (if you want Mac) or a reputable PC (Dell, HP, Puget). Yes, it will be expensive, but you are planning for longevity and want a robust machine.
If you are a light user – editing plus grading, short render requirements, mix of apps – then the last run of Intel 27″ iMacs (fully loaded) are also cost-effective for a Mac. Or do both. Get a high-end PC for serious work and a Mac M1 mini to supplement when you need to do something that’s purely Mac-based, like use FCP.
I would also avoid Nvidia GPUs these days. Apple has written them off, plus the supply chain is too affected by the bitcoin-mining idiots. Not to mention, Nvidia has other interests these days than the M&E space, like supporting the UI for automobiles.