Why is it?

Yeah, me too. I am lost and it’s not like I don’t understand English, Dialogues are just confusing (⊙…⊙ )

I think it's frustrating when the speech bubbles are just circles with no indication of who his saying what.
You have to rely far too heavily on context but even intuitive people aren't going to be able to recognize who is talking when there are 3-4 people shown in a cell with multiple speech bubbles and literally every character's mouth is either closed or covered / hidden.

Maybe it depends on the person cause I find it quite easy to keep up with the story and the dialogues. There are stories out there that are far harder to keep up with.

I still don’t know what is the deal between the bartender and that student ? I know the student has unrequited feelings for him , their relationship is so complicated

Student (Yunge) has had a crush on bartender (Natsuo) for a while and started working at his bar to try to get closer to Natsuo.
Natsuo has 2 sets of friends who frequent his bar--his college friends (Kosuke, Ayaka, Houjou, and sometimes Shirou [who is Yunge's gangster guardian]) and the other trio (the presumably cis girl, the cute trans girl Jessica, and the face mask physical therapist Tateshina [Natsuo's ex-sex friend]).
This trio loves watching Yunge flirt with Natsuo and they are all (not so low-key) rooting for the 2 to become a couple.
But after Yunge warned Natsuo he might lose interest or get involved with someone else after he goes to college, Natsuo started realizing he might actually like Yunge back, so he did what any emotionally constipated person would do and rejected him (not sure if he claimed it was due to age gap but more likely due to a claimed disinterest).
That was about 1 month before the most recent official English chapters featuring the 2. In those latest chapters, Natsuo + trio overhears Yunge get a phone call from the Oshibas, scolding him for causing Sasa (their female cat) to get prrrregante (since Yunge had stolen Natsuo's male cat, Mary--also the actual bar owner somehow) in order to get Natsuo's attention or some such nonsense.
But Natsuo/trio can only hear Yunge's side of the conversation which makes it sound like Yunge knocked up some random chick.
Yunge asks Natsuo to go with him to apologize since they're both at fault and somehow, despite claiming to be a cat lover, Natsuo completely misses all the obvious signs that Yunge is talking about Mary having apparently gotten Sasa pregnant. He thinks they're going to some random girl's house to apologize to her family on Yunge's behalf.
Natsuo is the perfect example of a character you might assume must be intelligent based on his quiet aloofness and huge Observer vibes, but this chapter highlighted what a slow ass space cadet the bastard is.
He realized something was up when they got to the Oshibas' home (he and Kosuke were college friends so he may have been there in the past and he definitely recognized it was Kosuke's house so he should've connected all the dots at that point) but he never fully understands what's going on until halfway into the conversation and that's AFTER seeing the 3 tiny kittens.
Then he tries to scold everyone else for letting it happen when the beotch obviously didn't neuter Mary (he and the Oshiba adults all proved to be neglectful cat parents--SHAME!!!)
Anyway, he finally connects the dots but once he realizes they don't actually need help finding forever homes for the kittens, he splits in a huff because he got overly emotional (maybe from seeing both Kosuke [his unrequited love] with his boy toy in their own home, maybe from all the confusion/Yunge awkwardly announcing he uses contraception, maybe from learning Mary had sex in the same house he'd been dying to for ages but never did, maybe because he couldn't keep a kitten--maybe a combination of all of these or something completely different lol).
So he gets home, scolds Mary, STILL DOESN'T MAKE A NEUTER APPT, then runs into Tateshina (facemask friend with benefits) he tries to kiss him but is rejected since Tateshina is rooting for Natsuo x Yunge.
Yunge runs into them right after Natsuo tried to kiss Tateshina and basically tells him he was gonna have sex with him but got rejected he'll go get it from somewhere else.
Supposedly, Yunge's feelings for Natsuo died in that moment--at least that's what he tells Natsuo and Tateshina (then later Yunge's high school friend group--Oshiba Kensuke, Masahiro Setagawa, and Asaya Hasekura).
But someone (probably Hasekura, I guess?) implies Yunge is likely lying and was actually extremely hurt and livid.
Back at the bar, Natsuo finally realizes he likes Yunge back but he thinks it's too late.

I don't normally care for younger seme x older uke/neko couples (esp with this kind of age gap) but for some reason I'm obsessed with Natsuo x Yunge and what their future holds.

Natsuo is an openly masochistic character in an overall pretty fluffy / vanilla series so he's always stood out and intrigued me.

Pairing him with a mysterious yandere-ish character like Yunge was a fascinating writing choice that honestly has me hoping they get their own spin off or something because it's getting harder to sift through all the chaos and fluff going on with the other characters to find any delicious nuggets related to these 2.

Thank u for taking your time to write this analysis. I was so confused about the two (￣∇￣") . So I guess it is the chasing arc for natsuo in the upcoming chapters

Thanks for taking the time to read through all my babbling, haha.

I dunno because from what I've seen in the Chinese raws, Natsuo appears in chapter 81 (but I can't read Chinese so all I can make out is that he tells Kousuke "no smoking" in his bar lol) and then Yunge appears very briefly at the very end of chapter 84 (and I think by then, there's been a time skip because the kittens are now cats ;_;).

Unless Yunge is one of the cross dressers that appears in any of the other chapters between 80-87, I don't think either of them make any other appearances, sadly.

I really wish I could find the Japanese raws so I could figure out what's being said.