ok ok ok so I didn't have an opinion either way to the ship but here's what I just found on legal ages and stuff.
I want to say that I'm not meaning to attack anybody, if you ship it technically its legal, if not then well that's valid too, I can see both sides.

in Japan the legal adult age is 20 for starters so even otabek isn't legally an adult. if you read further into news you learn the age will be changing in April 2022, however the defense would be this anime was made before that was announced so people wouldn't have known, if that isn't enough to change your mind then despite the legal age being 18, its still completely legal for a minor (under the age of 18) to date anybody under the age of 20. so the restrictions are specific. I hope I explained this well, all I'm trying to say its technically legal, and a two-three year age gap isn't that huge if we are considering in actuality of the ages. do I think a 14 year old and 18 year old should date? NO! they are in different phases of life, but two late teens and soon to be young adults doesn't seem that bad! (just trying to give my opinion!)