Hi,
Better share a link to the rack, so we can see the details of the different modules.

If you search on Youtube for Eurorack ambient or Eurorack Drone you will find many videos, some with in-depth explanations, especially for drones.

Modular is neither better nor worse for what you are looking for, what it is is very flexible and scalable, and mainly very expensive.
< Can I hook my modular setup up to logic, and record stuff from the modular in to logic all with the help of the expert sleepers es9? I know it allows you to record multitracks into the daw which is nice, but does it also work as an input?>
ES9 is basically an audio and midi output module. There are pre-amplified input modules, since you need to amplify the signal to Eurorack levels. Interesting that they have Envelope Follower, so you can generate CV from external sounds. For example the cheap Doepfer https://www.modulargrid.net/e/doepfer-a-119

I don't understand the two power sources. If you need more power you can include a source like https://www.modulargrid.net/e/4ms-company-row-power-45
I think Brains and Plaits overlap. I would stick with Plaits (or a clone) and add another oscillator with built-in modulation like https://www.modulargrid.net/e/erica-synths-black-vco2
You would also need an effects module, like clouds or Monsoon
https://www.modulargrid.net/e/calsynth-monsoon-aluminum
And a matrix mixer would be a good idea, to modulate the cv, it takes up little space https://www.modulargrid.net/e/crazy-chicken-matrix
And now, to finish for now, vca's
https://www.modulargrid.net/e/nano-modules-alt

Lastly, the two hundred pound thing is a typo, right? Because that's worth it Maths....
Best regards