I think it’s sort of the consensus that Yuuri is ISFP, but for the sake of completion (Vikturi pair) here we go. *Spoilers for the entire series*
Fi – Yuuri needs time alone to process his emotions. He also thinks about his feelings in terms of himself. He may not be aware of how he comes across to others e.g. Minami while he’s stewing over his internal dilemma. He has a more subdued way of expressing his feelings vs. Vik who is outright affectionate (dat Fe).
Se – From Viktor’s POV in the proposal episode, he observes the way that Yuuri was always looking for the right something, indicating that Yuuri is comfortable with sampling his external environment in the moment.
It’s noted several times in the series that Yuuri is in his element when he moves with the music during a performance. He’s willing to take risks like changing the jumps in his program on the fly.
Yuuri also has a tendency to stress eat from pressure before competitions.
Ni -Yuuri struggles to grasp a concept for Eros and needs to use katsudon to help him focus.
Yuuri thinks quite a bit about his future regarding his retirement from skating. Yuuri also sees the implication of his bad performance on Vik’s reputation. He thinks a lot about how he can’t keep Viktor away from the skating world and about the skating world without Vik.
Te – Yuuri makes some callous remarks in his internal monologue at the Nationals after he and Vik have that moment in the parking garage because LOL Vik’s methods didn’t exactly work. So his grip Te activates and does what’s effective in his moment of Te grip clarity?? We see this again in the finale internal monologue when Yuuri skates Yuri on Ice when he talks about Yurio being an idiot for using up his stamina or smth.
Yuuri wants to add more quads to his routine to match JJ’s difficulty score – basically to get the job done and get dat
marriage medal. Unfortunately, this plan backfires because he focuses too much on the technique rather than playing his stregnths and he’s unable to skate his best Eros in the penultimate episode.
A rather amusing example of his Te is where he tells Vik to take him sightseeing (more overplayed in the Eng dub, but I thought it was cute) because nah he got a plan to relax with his bae in Barcelona.