[kingrolo]

These days in my experience most people don't use a sidechain signal, just chop out, or filter, enough of the first base note so that it doesn't clash with the kick. People still refer to it as "sidechain" just because historically that's what it was. Most popular plugin to achieve this is LFOTool but also Shaperbox is used now too which is nice as it lets you cut in frequency ranges in different amounts. Its all about making it gel with the kick. You want your bass to be powerful but in the modern sound you always want the kick to win.

Yes phase alignment is important too. There's always a sweet spot where it just sounds "right". Plus staring endlessly at an oscilloscope to check they aren't interfering. Then doing it for hours and hours and wondering at the end if it sounded better before you started mucking around with it actually but your ears are so tired of it you can't tell anymore.

This stuff is such a rabbit hole. Lots of fun though.