It's an industry standard to consider anything below 24 hours to be just a connection where the layover points are just an utility to get you from A to B, not "a goalpost". This is is also how the regulation is interpreted by courts, etc. For 99% of passengers it fulfills the purpose, although there are obscure cases like yours where it's not the case. I sympathise with you, as I booked some of such "useful" stopover in the past myself, and there's no way for passengers to book them otherwise to not fall into this loophole, but ultimately you don't have a case legally speaking. Could airlines be more flexible? Yes, but they don't want to be and they don't have to be. I'm very much afraid that Lufthansa Group and especially Swiss aren't interested in your needs, they are very openly hostile to their customers. You can leave the feedback of course, but they don't and won't care. Them rebooking you to your preffered itinerary is the best you can hope for, they are not legally liable for the duty of care if they gave you a same-day option to get to your ticketed destination, and they certainly won't do it voluntarily.