I think you share a similar opinion to many users. I, as an installer i have to go with what the end user prefers so have an experience of both. I do love the colours of the older GUI and some find it much easier to understand.
As a system integrator and a Victron user myself, I fell in love with the new interface as soon as Venus OS 3.5 was released. It’s fast, minimalist, stylish, intuitive, and has a genuinely futuristic feel. On top of that, the system is constantly evolving, with improved menu organisation and an increasing range of customisation options to suit users with different system configurations. Overall, I find it far more convenient and enjoyable to use than the previous interface.