I think about the only time I ever use defer method these days is with something like zxcvbn, that is massive. I have a wrapper (asdfgh) that waits for it to be loaded, and handles this for me.
I do like the import() function since it's in browser pretty much everywhere at this point... I don't really worry too much about supporting legacy browsers these days. ES2020 is generally a safe to use target at this point. I also realize that some people will disable JS altogether, and while I understand the sentiment, it shouldn't apply to applications.