@applejack @Mr_NutterButter i was going to suggest something from Ghibli as well. It is by far the most approachable anime out there and not only is it approachable, it's also *really fucking good* while still carrying the anime/japanese charm and weirdness.
i'd go with spirited away as a starter. one of my favorite movies of all time.
if they end up liking it, then you can show them more ghibli films :) can't really go wrong there. they're all so beautiful and while they are typically marketed towards children, they still have that amazing quality where adults can watch them too and be totally bewildered.
then there's also the option of death note if you think they might like something grittier and more of a crime thriller with a supernatural element to it. i think that's a bit more of a risky play, but if you know that's something they are into it could work. if they like breaking bad, they'll probably like death note (if they end up liking anime at all, that is). could be used to show them how wide the medium is, after they've seen some ghibli.
my dad got super into naruto shippuden, watched basically all of it. i think naruto is a pretty approachable anime, i mean it was on disney xd for a time, but it is extremely long and has lots of filler so you kind of have to be in it for the long haul and really enjoy it to keep going.
i haven't personally watched akira (i know fuck me whatever) but i've heard many accounts of it being the first anime people have watched, even well into their lives, and really enjoying it and turning them on to anime more. one such account was vinny vinesauce, who for YEARS wasn't exactly "anti-anime" but just did not understand it and did not want to engage with it. he watched akira in i think 2021 or 2022 and has been slowly getting into more things that his friends have been showing him.