Read this thread. There are some comments about using React components for everything and never touching HTML tags and CSS. And they probably call themselves senior frontend engineers.
If not React it's just another abstraction (including whatever you come up with) that is arbitrary and shitty in a different way. Front-end/mobile is so boring and unimportant that it absolutely makes sense to just pick a thing and use it everywhere, and save your brain capacity for interesting problem solving. I say this as someone who's been doing front end for 10 years.
If frontend is boring and unimportant, what is exciting and important? saving records in a database? UX is what makes money and it is done through frontend.
Client side is only interesting in complex generic reactive programming problems, state machines, domain modeling in the client, local first patterns. The part about browser or mobile platform intricacies is very lame.
Coding and algorithms are just some of the tools available for frontend and software engineering. UX is another layer that most software engineers can't grasp, it involves art, sociology, politics. Calling it boring and unimportant when you are not good at it is a misunderstanding of software's true purpose.
No one even mentioned agorithm. If you are really user focus as you claim to be, you should love cross platform, focus on delivering values and not be a simp for these "native" tribal knowledge. Talking about misunderstanding software's true purpose.