Please, please please have reasonable bounds around that if you do want to use a responsive font-size. `clamp(10px, 1rem + 0.25vw, 60px)` (say) doesn't harm anyone else.
There are some worst offenders who chose the fontsize based on the size of the viewports... and it get's ludicrous big at my work, where I have an ultra wide curved monitor.
It's definitely a fascinating game to try websites Full Screen on an ultra wide. I definitely tend to stick to FancyZones for most browser windows to get "normal" breakpoints, but every now and then it's fun to play with sites and see which ones tested extremes in responsiveness.
I get a lot of flak that my blog [0] scrolls horizontally by default when JS is enabled, because that is intentionally weird, but it's one of the only websites I know of that is "readable like a newspaper" when full screen on an ultra-wide monitor. Some posts you can read the entire article at full screen on an ultra-wide with no scrolling at all. I'm proud of that and I like that for my own enjoyment, even if few others appreciate it.
