I (23/f) am bored and put off from my boyfriend (26/m)/apartment with him

So we are dating for 3 years now, live together for 2 years.

We have a cat together and if you asked me just 2 months ago I would have told you that I would marry him on the spot.

But something just has changed.

I recently started to see his messes around the house and confronted him about it.

We had a big fight, he promised to be a little more proactive and do projects with me around the apartment.

He is a radiology resident in his first year and works about 10 hours a day, so I take almost every chore because I have much more free time. I am and was totally fine with that!
But his personal messes just make me anxious and he doesn't want me to touch them either.

It's things like piles and piles of old notes and paper just stuffed in our ONLY living room shelf, or old boxes from our move, not sorted out.

He tends to hoard crap and I hate that. I am a neatfreak, I like to sort through my stuff again and again, throwing away things I see no value in. (No I am not Marie Kondo, I did that since I was a primary schooler)

He on the other hand hoards useless crap that serves no purpose, and doesn't even put it away in an orderly manner.

So, that was our fight about.

Post-fight, before making amends, I thought about our relationship a lot and realized for the first time, that I can totally exist without him, without anyone.

In one year I will finish university and stand on my own two feet.

Somehow that realization was like a switch to me, it really changed my attitude towards him and this relationship.

I just want to live in a space I enjoy, with my little kitty and yes, also with him. (still!)
But I don't have to. I can do whatever I want. Just because we are dating for a long time, I don't have to CONTINUE dating him, right?

Usually I am a big defender of "fixing" and not "throwing away".

But the reason why I venting right here, right now is this:

I was with family over the last week, with my kitty. He was at his family. (He hasn't seen them in about 6 months and I didn't want to come with him, which is fine and normal for us.)

And I came home to our apartment a few hours ago, and it hit me like a crushing wave.

I am SO unhappy in this apartment. It's uncomfortable for me, only a tiny bit how I like it.

It's cluttered, it's small and crampy and just feels off to me. I feel like in a cage. (It's 55 sqm by the way)

Now of course I don't know if it's because it's empty and he is not there, but I feel majorly put off right now.

This is such a strange feeling to me. I started seeing him when I was only a 19 year old uni freshman and right now it feels like I am just done with that phase of my life.

Is that strange? I feel so alienated right now..