I didn’t want by any means insinuate that your question was stupid. Simply that it is really hard to compare the two. And yes, comb filters, modal resonators, physical modelling and twin filters are all very different, though they certainly have an overlap in certain areas.
The similarities are probably stronger between Elements and Rings than the differences. This has been covered already many times here on the forums, so I’ll just give you the short version and invite you to look up the many threads on the topic here.
What Elements has that Rings lacks: built in exciter section, reverb.
What Rings has that Elements lacks: polyphony (in the sense that it can play up to 4 voices so release of sounds is not cut off, but it still only has one trigger and v/oct input), synmpathetic string / inharmonic string physical modelling. So there is still value in having both, but they also have quite a bit of overlap.
I’m not sure you can really do the bubbly watery sounds you can do with a twin-filter design like the Klangbau one. The best thing is always: watch as many demos as you can online and if possible see if you can try the modules out yourself in a shop. Your ears are the best judge. None of us will really be able to tell you which module best fits with you.