Mac computers

I’ve used apple since I was about 15 years old i will never buy another Phone since i started using Apple ..in september 2019 I saved and Bought myself A mac for Photography editing reasons and I though it would be the last of my problems but I never should have bought it as i had Endless problems with how slow the mac are even just switching on I took it for repair and they can’t even believe it takes 4 days just to update even when i erased everything from it ... very disappointed!! I saved my butt off for a piece of **** ! I want answers ***