How to make the job exciting/challenging?

Hi folks! About two years ago I've moved from Portugal to Germany, to pursue a job opportunity. Currently I'm in a situation where I've been working as a (senior) in-house developer for a company in the greater Berlin area that I absolutely love. Problem is, even though the business relies heavily on their software, they don't take software development very seriously. Half of the technical leadership has left and hasn't been replaced (yet) and every single one of our teams is just doing whatever the manager of their business unit wants them to do, there's no alignment whatsoever going on between teams. Even our most senior back-end developers are working on slightly adjusting the styling of text on our website, for example. Don't get me wrong, there are no bad intentions, folks in (tech) management simply don't seem to know any better/different, but it feels like we could get loads more out of our developers and hopefully entice them to stay instead of leave like the bulk of our good engineers already has. The company provides all the means we could wish for if we want to experiment with something, learn something, try something new, whatsoever, but there's absolutely zero natural challenge in the usual day-to-day work.

I'm wondering what you would do in a situation like this (not wanting to leave the company, but being in dire need of more challenging work). How would you convince management they could get a lot more bang for their buck if they actually provided their people with challenges? What would those challenges look like?

Thanks for your time or Dank für Ihre Zeit (I believe is what the Germans say).