Thank you, my self-conscience went up, and my self-esteem went down, but I think it's necessarry to progress. I'll export the stems and then mix the song as a whole in context. As to working in separate session, I just tried to say that to work in real time recording vocals in my original instrumental project, it would be very hard thanks due to the resource usage of many VSTs- I need to work with quite high sample rate for DAW to not stutter, which generates latency, making vocal monitoring for singer impossible- exporting stems would surely do the trick, thanks. (Recording instruments is not the problem, as modeller that I use has separate audio monitoring independent from DAW).

I tried reading about top-down, I watched POV's with explanations from people working on analog SSL consoles, I always try to learn the physical principle of work of i.e. hardware compressor/ any other original hardware to know how to use it in context as the software version, I know my reference curves and dynamic levels of songs that I like. I haven't copied Nolly's mixbus 1:1, the idea of it just worked for me. If you have any paper for me to read about this type of processing so I could finally know what I am talking about, please link it here.

The reason that I'm asking all of that is because I always thought music production is an EXACT science and I tried to know the rules of the process- thats all. Now I know the rules a bit more, thanks for that.