Google n-grams isn't all that sympathetic to my account, in showing a long history for 'extrovert' and suggests 'extravert' is actively dying out.

But the history may not go back far enough: https://blogs.scientificamerican.com/beautiful-minds/the-dif...

'Folklore has it that when Carl Jung was once asked which was the correct spelling—ExtrAvert or ExtrOvert—Jung's secretary wrote back something like, "Dr. Jung says it's ExtrAverted, because ExtrOverted is just bad latin."'

[...]

'According to the Oxford English Dictionary, "The original spelling 'Extravert' is now rare in general use but is found in technical use in psychology." That's correct. If you look at scientific journal articles, virtually every paper uses the spelling ExtrAvert.'

In my accent, at least, I pronounce the phrase 'extr_vert-introvert' with an open A, contrasting to the pursed O of introvert.

But if I say the word 'extr_verts', by itself, I pronounce it with an O, identical to 'introvert'.

It's difficult because for me, at least, in my accent, both are degrading to an unstressed vowel anyway, so it's a fine gradation.