What I believe you're noticing is the the adoption of ideas under the (poorly named, IMO) UX umbrella. UI design is either considered part of it, or close enough to get the UX/UI slash treatment. It's not quite there as an idea— people can't decide if UX people are the same or UX Researchers are different than UX Designers or if UX Designers just do wireframes and user flows or also design UIs or if that's left to Interaction designers, blah blah blah. The base ideas seem to be an amalgam of human factors engineering, graphic/media design communication theories, and quantitative marketing type work.
While there are hundreds of trillions of articles on the topic by people thirsty for medium claps, I think the most interesting jumping-off point might be an image search for ux design process and using the charts you see to guide an exploration. The Nielsen Norman group has a TON of stuff online about the topic. Not just design itself, but measuring the maturity of usability organizations, research techniques, best practices and data strategies... I mean all kinds of stuff.
I think a lot of the ideas are tremendously valuable but much of what's written about it feels a little bit too much like marketing material. The ideas are presented a bit too confidently considering how often they change, and too much has that LinkedIN magic bullet kind of vibe. Also, like tech, the industry is subject to spike trends (like tech saw with NoSQL databases) and pendulum swings (like centralization vs. decentralization of services, thin vs thick clients, etc.) For something a bit more structured, the former Lynda.com, now LinkedIn Learning has some really fantastic educational resources on modern design of nearly any stripe.
I'll swing back through if I can think of any specific resources worth checking out.
As a developer who always had an interest in UI design but has zero formal education in the field, I be really interested to know more about this. Could you maybe explain some of those strategies?
My subjective impression is that design has shifted from building a consistent "language" to a more goal-driven and data-driven approach today. The product owner defines a list of user stories and UI is primarily concerned with making those user stories as frictionless as possible - even if this means a less consistent overall design snd even if it means that less common features become harder to use. Performance is measured in a feedback loop through telemetry and A/B tests.
I might be wrong though, so I'd be interested in a qualified opinion.
(Also disclaimer: I grew up with Windows 98, ME/2000 and XP. So I guess this is my "good old times" spot then, where I'm wearing the rose-coloured glasses.)