The dot over the »i« or »j« is called a tittle.
The dots of the lowercase »j« have a slightly larger dot compared to the »i« to compensate for its form.
(not neccessory in all typefaces)

Thanks I've been looking everywhere for that info without luck. So much so that I thought I had imagined that there was even a name for it

tittle |ˈtitl| noun [in sing. ] a tiny amount or part of something : the rules have not been altered one jot or tittle since.

• archaic : a small written or printed stroke or dot, indicating omitted letters in a word.

ORIGIN late Middle English : from Latin titulus (see title ), in medieval Latin ‘small stroke, accent’ ; the phrase jot or tittle is from Matt. 5:18.

"The dots of the lowercase »j« have a slightly larger dot compared to the »i« to compensate for its form."

Where did this come from? Sounds like more "type logic" like the silly serif lore.