Hi Schwuah,
You are very brave, I think, if you want to have a (modular) synth and then never add or change something to that system. I am not too sure if that's possible ;-) I am totally the opposite of that, I keep changing, keep adding modules and I couldn't imagine a modular synth that "is not allowed" ;-) to be changed for let's say two years or so. So I would admire you if you could stick with your initial modular synth and not adding anything, which is good for your wallet, certainly, however I doubt if you can make it :-)
No LFO guy? Ha, ha, I don't mean this to sound bad or something but there again, we are our total opposites :-) I love LFOs, got quite a few of them and still consider to get more. So other than envelopes, how are you going to do your modulation?
Good luck with your plan, I hope you can stick to it :-) Kind regards, Garfield.
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads