"No, we can not do this because this trip is too complicated for us, so it will obviously be too complicated for our users"
This is an assumption made by your UI designers. And the only way to solve this problem is to perform extensive research and testing with users.
The most striking truth of the curve is that zero user gives zero idea. – The Norman group of Nielson
You need users to participate in the creation of your product. It is wise to test your wired structures with your identified user group and to get positive feedback from your users. Be sure to document your test process with video and audio so you can then make a short presentation to your UI design / development team.
In this way, you can validate your designs and if your users give positive feedback about your designs, the designers of your user interface will have to suck it and follow your wired structures.
However, in my work, I think it's best to properly convince other members of your team, so that they are just as excited and motivated to deliver a good product. I also think that all participants should compromise and never focus on any particular project / idea / concept.