"Hey", /ˈheɪ/, has a dipthong /eɪ/, so é is precisely the first half of that dipthong. It may feel like it's between the “e” in “bet” and “ee” in “see”, but using the dipthong you don't have to guess it.

Technically true, but this concept is foreign to English speakers. English relies heavily on diphthongs and can’t separate the sounds in their head. Simplest example is probably the word “no” which is very much a diphthong.

That’s why they always have such predictable accents in another language.

I've been speaking French since pre-school (albeit in North America mostly) and to me é always sounds more like the English short i (as in "tip"). I'm becoming increasingly convinced that everybody on Earth but me is wrong about it.

Only if your accent is relatively close to General American or Standard Canadian :)