I tell anyone entering the job market or is a young professional that absolutely no job is worth losing yourself over. Your skills change over time and will never leave you completely. I’m a competent designer, a reasonable developer but the most marketable skill that I didn’t actually develop until my late 20’s was soft skills—mostly developed by gently explaining to tech illiterate coworkers why what they wanted developed was impossible, impractical or just a bad idea.
I did this by treating every coworker as if they were the client. Be polite, professional and let them know that you want to solve their problems. It’s sounds stupid but people just put their guard down if you lead with, “I’m here to help you”. You can then have more honest conversation about all the bullshit keeping you from doing your job, provided it’s phrased as matter of fact and sprinkle in niceties.
The cruel irony is that this same disposition that started as a way to make me a more effective developer ended up pushing me into a position where I don’t get time to develop.
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.