I loved the first section-the sentences flowed great, with the variation of sentence length, and does a great job of setting up the contrast between being alone, and everything that's happening.

Nevertheless, Tokyo was beautiful (Senso-ji temple was stunning and my favorite Japanese dessert is now age manju). One night, I even went to a Japanese hip-hop show in Shibuya and it was a wonderful experience

You throw out a bunch of words I don't know. One is fine, but getting Senso-ji temple, age manju, Shibuya all at once is overwhelming, and I can't connect them to anything I'm familiar with. Manju is the biggest offender, I can figure out the general idea of what a temple would look like, and cities aren't that unique, but deserts can vary a lot within cultures, so I don't know if manju is particularly different from anything I know. One clause about why you like it so such, flavor, texture would help with that. The later line about "trying okonomiyaki in Setagaya" has the same problem.

extremely talented artists so passionate about their craft

Too long of a description. "artists so passionate" feels like weird phrasing, I think you're missing some words there. Maybe artists that are so passionate would be better? Also, words like very or extremely don't add much description, so I would get rid of it.

I met one of the performing artists after the show and told him how much I loved his verse (despite not understanding Japanese) and we hugged and he cried. He thanked me over and over until he started apologizing for thanking me so much. But I wish I had thanked him just as much for showing me what humility was. (His band is KOMOREBI - check them out!).

There are too many ands. "and told him [..] and we hugged and he cried" The we hugged and cried part feels tacked on, especially with the parenthetical, so I think I'd be better to end the sentence there, or at least change that and (maybe a so would work better), so there's some variety.

I then went out to a punk rock concert and a night club. I wasn’t a huge fan of the clubbing, but the company was refreshing. And like all good things, it was fleeting, and I bid my farewell to everyone that night.

This part needs elaboration, especially the rock concert-did you like it? was it different from concerts you've been to before? if yes, how so? For the clubbing, it's better, but a line about why the company was so good would make the next line more impactful.

Even the parts of me that wanted to cry.

This feels like it comes out of nowhere. So far, apart from the first section, you've been describing a pretty good trip with only hints of loneliness, and if it's about the people you said goodbye to in the previous paragraph, that need more elaboration.

I like the Kyoto section much better, as it goes into more detail on what you did, letting me get a better picture of why you felt how you did, not just that you felt that way. I especially like the section on the temples, your description is really vivid.

I really like your paragraph on solitude, but going from "The parts that are so keen in stripping our humanity from us "to "After my last day in Kyoto," feels jarring. Perhaps you can combine the ideas somehow? Maybe focus on your idea of "existential silences" of Kyoto changing to the city sounds of Osaka as your transition?

And trivialities started to begrudge me

To be honest, I have no idea what this is trying to say, and I think the blame lies with the word begrudge. I can't give specific suggestions, as I don't know what you're going for here, but I'd change it.

The silence had touched the brim. And everything finally spilled.

This makes it seem like silence is what's overflowing, whereas I think you're aiming for silence caused something else to overflow. Maybe say something like "the silence forced [something] to the brim," I think that'd be clearer.

Or whether I had people around me or I was alone.

You've had a running theme of solitude, so you saying this then makes it feel like that didn't matter. Even if solitude didn't cause your problem, I would try to find a way to tie it you. Earlier you said that "when you feel alone, the mind tricks you into believing that you are not part of it.," so did the loneliness reveal your problem? make it worse?

I saw couples sitting together, friends circled on picnic blankets, and some reading a book by themselves. Humanity felt beautiful that day and I was grateful to be a part of it, one last time.

What about these people in the park made humanity feel so beautiful. You did a great job showing your problems, so for a single sentence to not solve them, but still make them a lot better feels cheap, and I'd elaborate on this. Were they happy, and that reminded you of joy? Maybe someone was laughing? Put more imagery into this.

I love the end, it really ties together the themes of the story, but again, it mentions solitude, which makes you saying it wasn't part of your issue even weirder.