Kudos for the first attempt. I just got my copy of Patch & Tweak today. The shrink wrap is still on it. I'm going to read it cover to cover. I think you definitely want to do that too.
Lugia suggested more time in VCV Rack. I second that. You're about to spend thousands of dollars on gear and judging by your first attempt, you're not going to be all that satisfied. That's not a judgment or criticism of you, just how much value I can see you getting from what you're going to spend in time and money.
When in VCV rack, learn how to use the Clouds module. It's popular for creating ambiences. Is it necessary? No. But it's great for creating very interesting and evolving timbres. While in VCV rack, you might want to look at modules that are logic based. You can find pure logic modules (AND, OR, NOR, NAND, etc) and there are modules with logic as a function like the Rampage by Befaco. Hardware sequencers, even though you have one in the Brute, are very handy for controlling CV and gates for more than note pitch and triggering volume envelopes.
The bottom line is that I'm thinking you need a little more experience and knowledge before spending your hard earned money on Eurorack. I have only one module that's been pulled out and put away costing me $160US. There's another module that I rarely use that cost me $184. So I'm out $350 and consider myself lucky. I studied a lot of modules and spent a lot of time in VCV Rack, and ordered everything in stages. Along the way I made TONS of revisions after using the modules and gaining more experience.
Hope there's some useful advice above and I sincerely hope you get a system that meets and exceeds your needs. Keep posting and don't get discouraged. A few more revisions and you'll have something tasty sketched out.