First, I'm not a genius, nowhere near… I'm just determined.
Let me explain why I'm always recommending to install and use un-patched Catalina, these are the main motives that I recall now:
- A MP5,1 with an upgraded AirPort Extreme AC, don't need any patches at all, you run exactly the same install as any supported Mac.
- You are running exactly the same code as a Catalina supported Mac and can install your drive on a supported Mac, or my preferred way, use a direct hardware VM with Fusion/Parallels, and do software updates. With a patched Catalina you will have problems doing it and every time you will have to install an updated patched Catalina over your current install since you can't update it.
- Documentation, this is a pet-peeve of mine and will seem stupid for most, but the patches don't have a central repository with versioning/release logs, if you need to debug/audit something about a patch you will have to do endless searches to try to find something. I know that for most people here this is not a problem, but it's for me and it's unsustainable in the long run.
- Security/compliance, another that for most people it's not a problem, but you can be in trouble running patched macOS. People commented here more than once about this.
Anyway, it's a personal decision to do it one way or another. In the long run, running a direct hardware VM to install/update will be easier and a lot more maintainable, while you have to spend some time to get it going initially, you will be very pleased with the easy of updates and the time you earn not having to create an updated patched install over your Catalina disk at every new update from Apple.
Btw, a new way to run un-patched is being developed that is very promising, using OpenCore as a boot loader, and will make things easier when it's ready. This will probably make us finally have software updates, Continuity and HEIVC acceleration natively with Catalina. Until OpenCore is ready for prime time, direct hardware VMs are still the best option to install and update.