Your body and mind is just a bag of chemical soup, undergoing a constant reaction. Your tangle of nerves and synapses feed a mess of neurons that are wired in a circuit that gives you that spark of consciousness. But none of this is a fixed system, and your body goes through constant change. As one neural pathway dies, another one is rewired and the circuitry is now different.
You can play the game of debating the Ship of Theseus, but who you “are” or “were” is just an illusion. Our memories are just the old circuits powering up, but even those change over time. Your memories are a false representation of the past because they only ever exist in the present and you’re at the mercy of your own perceptions.
You “are” until you are not. So do what feels good —Kiss your loved ones, hug a tree, and be kind to yourself and others while your bag of soup ain’t leaking.
Speaking as a designer, it’s important to separate the style/trend of a UI from its function. I think what you’re looking for is actually UX design.
As a discipline, User Experience uses evidence-based research to understand how and why users behave they do. This leads to specific design patterns and principles that underlie all the good UI design seen from the giants like Apple, Google, Microsoft, etc. It gives you the language to evaluate designs. This is the foundation of your UI and the rest is just style — fonts, colors, imagery and icons which is subjective and less important. I lost ambition to be a trendy UI designer, so every design looks the same, but usability will shines through. Clean, simple and accessible is timeless.
Study the articles from nngroup.com. They pretty much established the field of UX Design, with content talking about user behavior in the 1990s. https://lawsofux.com is a more attractive and consumable option, also heavily influenced by NN Group. Finally, accessible design is good design for all, not just those with disabilities. Understand the guidelines set by the W3C for accessibility, like minimum font sizes or contrast ratios for colors.