Ok, so I was actually really, really curious about this, and it seems like <u> has actually deprecated from its usage as the underline command (starting from HTML4 onward), and starting HTML5, it is now exclusively used to denote a squiggly line: ﹏﹏
Sometimes it’s colored and appears beneath incorrectly spelled words:
Talk about today I learned, eh?
I was also messing around to make sure brackets work for all commands, and I will now be adding those alternatives to the OP.
@Szaal @ParrotWatcher Do you guys mind if I add your tips to the OP? 