Nice, sounds like you have a good idea of where you want to go and the fact that you've been working with VCVRack is great. Now it makes sense that @Lugia gave you an "Ok" rating on your 3U row, his "Ok" being most people's "Well done" lol. So, next steps, the Mantis recommendation makes sense and seems to be the general path forward, but since you're just starting out I'd limit my initial buy to 104HP and then grow from there. If you set this rack aside (but keep it for comparison) and make a new rack with @Lugia's advice in mind, working to maximize functionality to HP, you should get pretty close and then we can review again. SSF Tool-Box is a great suggestion, and I'd also suggest you take a look at some of my favorite modules for this stuff, Kinks, Links, Cold Mac, Zadar, Batumi, Ochd, Intellijel Quad VCA, and of course Maths. Now, don't pick all of them of course, but a few would go a long way here!
my tunes: https://stevehand.bandcamp.com/