Where to start?

I’m slowly learning to master my Minibrute 2S and have decided to go Eurorack for more options. So I have bought a 6U Rackbrute that wants to be filled with modules.
But I have a limited budget and it is so hard to decide what to start with.
I want to create something like ambient music and maybe try to create some simple self-generating patches.
But the main purpose is to add new functions to the Minibrute.
I think I need some dedicated LFO:s and EG:s in the rack but I maybe can start with the 3 LFO:s and 2 EG:s in my Minibrute?
Maybe I do not need the step sequencer but I already have it and have used it as a battery powered stand alone unit for another synth.
I would really appreciate if I could get some feedback and some advice in what order I shall buy the modules I’m thinking of or the ones that you maybe suggest as better choices. I have not the money for buying everything at once, but maybe within half a year :-)

Well, I don't have great answer for you since everyone uses their rig differently. You have several directions you COULD go in. But each one requires a substantial investment.

So, let's start with your MiniBrute. You have basically a "synth voice." It's a complete synth architecture with semi-modular jacks.

What is the MiniBrute lacking for you? You can always add Eurorack effects. Eurorack effects can differ from pedals or outboard gear especially if attributes of the effects can be controlled via voltage. Take for example Tip Top's Z-DSP. The effects are fine. But what makes them shine is the ability to modulate them. Think of a Clouds clone, distortion/overdrive, ring modulation, etc.

Filters. Having different choices in filters rather than just what comes with the MiniBrute might be a tasty choice as well. You could also add different types of VCOs or sound sources rather than what comes with MiniBrute... then run those VCOs through the MiniBrute architecture.

But for now, there's a limited amount of money to go around. I would try this: whatever you've already bought... put it in the rack. Get the Disting module and try out ALL of the effects in it. The Disting is a pain in the ass to use. But it's basically a nice collection of different module functions you can try out with your MiniBrute. If you find something that you use over and over... then maybe you should get a dedicated module? Take for example the quantizer or the sample playback functions. If you're constantly using one of these functions, then start looking for a dedicated quantizer or sample playback module. Then you have a roadmap to which module(s) you should get.

Thanks for the advice!
I think I start with µOsc-II, A-120, Swamp, µ4xVCA, 2Multi and Disting for checking out which of the effects I need as dedicated modules.