[ry_ry]

Out of curiosity, when was that? Modern frontend has many issues (npm is at least a hundred of them) but browser compatibility is a solved problem for the majority of purposes.

HTML had been stable since forever, and browsers will render pretty much any old shit you throw at them without too much cajoling. SVG/canvas were the last things to be cleaned up iirc, but they're pretty usable now.

Most of the sharp edges on JS' DOM API implementations were smoothed off ages ago and if you want to use the newest features stuff like babel and typescript transpile es6 back to es5 with selection of polyfills. AFAIK safari still can't round opacity properly, but since that's usually a stylistic thing just use css.

Vendor prefixes in css have been less relevant for a fair while, were easy to use if you wanted to throw some @keyframes down, and are a non issue of you use an auto prefixer of some description.

The only problem browser is IE11, which had some admittedly wacky implementations and out-dates most of the modern frontend stack by several years.

There are still weirdnesses (Firefox's font rendering, literally everything Safari does, features being implemented and deprecated simultaneously) but nothing insurmountable.