that reminds me speaking of future career free! head canons I have a couple I’m proud of ok so here they go
Nagisa
Nagisa ends up listening to his parents and is pressured into business school which he hates but this time bc he has his friends he refuses to go to a dark place and he uses his bussiness degree and combines it with his love or making people happy and he starts his own children’s toy business

Rei
I really like the future fish ending as well but I always imagine Rei as a free lance writer and and artist although he could have easily gone into math or science he abandons it a goes for the per suit of what’s beautiful I imagine him using math in his art though. I think Rei would be one of those artists where his work is super abstract and no one knows what he’s babbling about half the time

Makoto
I love the idea of Mako being a teacher it’s not my head canon but I adopted it and added to it like I imagine Makoto going to a university close by and getting a job at the swim club to pay for his college bills He becomes one of those really cool lit teachers that everyone loves and becomes a really big mentor for his students and gives them advice in stuff eventually he upgrades and becomes a school guidance councilor a lot later in life

Haru
my old head canon for haru was for him and Rin to go pro separately and they follow each other for a bit but then they decide to go there own ways but they meet up again surprisingly when they both make the Olympic team but never mind that bc kyoani took a giant dump on that one and yes I’m salty about it