Discolure: I have the Ornament & Crime with Hemisphere firmware, a Clouds clone similar to Monsoon, nanoRings. No experience with Odessa, Quadrax and Marbles, but know the concept of Marbles and Quadrax. Had semi-modulars for 4 years and fully into eurorack for another 3 years.
I'm not really sure if you'd consider yourself a beginner or not, as you seem to have a lot of electronic music experience but not as much eurorack experience. This is why I find a bit difficult to tell you if these modules are good choice for you.
The modules that you have chosen are understandable, as they are quite popular and versatile. Lots of eurorack videos online seem to include at least one of these modules. I've been drawn into eurorack by demos of Clouds too.
However, as farkas mentiones with Quadrax, you've chosen some top-of-the line modules, this makes them very appealing and versatile but also somewhat complex to understand. Ornament & Crime has a lot of "modules" in it, Monsoon has multiple modes in it with button combinations to remeber, and Rings is notorious for being hard to tune.
I can image that there's a possibility that you put this rack together, the modules are difficult to tame or button combo's are hard to remember, you have to read hundreds of pages from manuals and forum posts, and you eventually drown in all the possibilities.
If you consider yourself a "beginner" in the eurorack realm, the learning curve might be less steep by swapping one or two modules for more "basic" modules. If you find those too basic or easy to understand, you can always get the more fancy ones.
I'd agree with farkas that Plaits might be a good choice, for example instead of Rings. You can use a second-hand Quadra instead of Quadrax, or something like Nano Modules Quart. Maybe even a second Ornament & Crime, that one helped me a lot with a bunch of different eurorack concept because the screen gives quite a good visual feedback, and includes things like a scope, tuner, envelopes, logic, slew etc. Only down-side is that it's not very suitable for audio but mainly for CV. I have no experience with Odessa but it looks a bit intimidating. You could swap it for maybe one or two Befaco Pony VCO's, those have through-zero FM and wavefolding, cross-patching the two might give similar complexity to Odessa but not sure.