[Aperocky]

Clean code == elegance > complex in my books. I'm unsure what your definition of elegance is, but for me it's simple and clean. Any complex things should be slimmed down to simple thing or a small combination of simple things. If it's faster, than it's even better, if something is both cleaner and faster, I can't think of a scenario that I'll not side with that.

Premature optimization is root of all evil. It seems the new system is coping fine with demand, are they at the risk of falling over? If not, then there's no point in trying to prematurely optimize it, especially if change made it slower. Even if optimization is necessary, a good optimization strategy should not have made anything slower to the point that it is noticeable.

All in all, it seems like a successful rewrite story, which is not easy. Many times rewrite makes things worse and not cleaner and simpler.

I'm not very qualified for personal advice, but try greener fields either in org or elsewhere, as software engineers we are valued for the ability to create, and should not get too tied up to our existing creations.