Essentially, the argument made by Butterick and others is that choosing Arial as a font is not a choice but indicates the absence of a choice, since it is a system font. [1] At the very end of that page he writes a few paragraphs exactly why he dislikes Arial.

Regarding alternatives: "[...] Arial is permanently associated with the work of people who will never care about typography. You’re not one of those people. So use Avenir. Use Franklin Gothic. Use Gill Sans. Use one of the fonts listed in Helvetica and Arial alternatives [2]. Or use something completely different. But don’t use Arial. It’s the sans serif of last resort."

[1] https://practicaltypography.com/system-fonts.html

[2] https://practicaltypography.com/helvetica-and-arial-alternat...