@Gednaa
Oh no ☹️ No, you don't at all. There is also no such thing as an iMac Pro 5. There is the iMac and the iMac Pro range. In fact you have the cheapest entry level 27" iMac. It's still great machine but not the most powerful and if you're using it for pro music software you should definitely have more power in the CPU and more RAM.
If you look back at the posts on the previous page where we both posted specs you can compare our machines. There is a big jump from the entry 6-core i5 to the 8-core i9 and my GPU, which is what makes the difference with the game, has 8GB VRAM, yours has 4GB (which should still be great BTW). From memory, mine cost around £2,200 with the upgraded CPU, I upgraded the RAM myself, Apple charge way too much for that.
The iMac models are here - https://www.apple.com/uk/imac/
The iMac Pro is here - https://www.apple.com/uk/imac-pro/
Easiest way to tell the difference by just looking at them is the colour. The iMacs have a silver casing, the iMac Pro has a black casing.
You can never compare Windows PCs and Macs. iMacs have everything in one behind the screen and also use what are essentially mobile components. Your self-built PC was a tower presumably? The PC would have had much better cooling although I have never had a problem with Macs overheating and yes, they do get hot. The only true upgradeable desktop machine Apple make is the Mac Pro - https://www.apple.com/mac-pro/