I have heard a ton of UX/UI discussions about fonts, colors, sizes, borders, elements, etc.

All that is a bullshit. The user would get accustomed to whatever font and size your app provides.

There is only one UX solution I am absolutely fond of. Google Authenticator allows the previously shown code for an extra five seconds after the app says it was obsoleted. This is great.

But I could live without it if they fired all UX engineers and I got my share of the released money.