Font Sizes and Golden Ratio as a Non-Professional

For most of my projects (mostly scholar), I tend to use multiples of 3 for both my font and shape sizes, there’s no real foundation behind my principle (except for intuition and maybe something I picked up by playing Minecraft), but if I had to rationalize my decision, I would probably say it has something to do with 3 being a small prime number that allows me to be consistent with my sizing.

Regardless, I’ve presumed so far that font size is not necessarily as important as the overall balance and harmony of the project, and as long as it fits within it doesn’t matter what size it is (especially since font sizes tend to affect different fonts in different manners).

However, I recently came across a video explaining that it was best to use multiples of 1.618 (the golden ratio) for font sizing.
As far as I know, there’s no real basis for the use of the golden ratio regarding aesthetic purposes (contrary to those of optimization), but I’d like to get a more informed opinion on this, as well as to know what someone more educated would think about my “rule of threes”.

The Golden Ratio is a mathematical oddity. I’ve never viewed it as having much, if any, relevance to graphic design outside of philosophy and the ancient Greeks. Our brains don’t automatically perceive the ratio, but we do perceive halves, quarters, thirds, and perhaps fifths, which can, in many instances, help create layout cohesion, balance, harmony, rhythm, and simplicity. But the Golden Ratio formula below, nope.

As for type, if it’s meant to be read, no matter what else is considered, legibility and readability are always the most important concerns.