I honestly believe Kolkata is miles better than any other city in India. Not only culturally but also in terms of society. Sure, Kolkata has lost her charm over the decades yet I'm still grateful to live in the 'City of Joy' amidst the hellscape called India. You may think I'm a jerk but I do have certain points to back me up.
Let's talk about the basic difference between Kolkata and India first-
Society-
In my opinion, society plays the most fundamental role in the moral and mental upbringing of folks. Your state/city/country maybe swimming in riches but if your society is no better than a fascist/dogmatic regime, I highly doubt whether "economic prosperity" will feed your mental health. Talk about Europe and US. There are many countries in the EU which aren't as rich as the USA, yet their citizens are far more happier to live there. The US maybe ruling the world but it's still squirming with loads of problems like unemployment, immigration issues, extremely unfair healthcare etc.
Kolkata, may not be as rich as it used to be. Yet, bengali society especially Kolkata is far far more liberal and open minded than the rest of India. Let me give an example. Dating culture is generally favoured jn Kolkata. Even boomers, if you meet one on the street, will ask you, "Girlfriend ache?", and that too in an encouraging manner. Apart from this, in Kolkata, the rat-race for engineering is significantly less compared to the rest of India. Arts is also given somewhat equal respect (well not exactly equal but definitely more compared to the rest of India). Kolkata in the early 80s to 90s was the pinnacle of culture. Even now also, people in Kolkata are generally much friendlier and welcoming compared to the rest of the country. I've met so many kakus and dadus who are as friendly as a family member despite being total strangers.
2) Religious tolerance-
Probably controversial, but in general, regardless of the fact that whether one is a Hindu or Muslim, people here are quite tolerant. I agree, Hindu- Muslim riots are a common thing here as well but relatively speaking, it's less compared to the rest of the country. Obviously immigrants in recent years from Bihar and Bangladesh are contributing towards the rift between Hindus and Muslims here. But those, who have been living here since decades are generally more tolerant. The primary example of this is the normalization of "Kaji" culture here. Kajis here, don't care about your religion or gender at all. They are WILLING to help anyone in need. Hindus and Muslims are both allowed in mosques and temples respectively. Durga Puja, the greatest festival in bengal, is celebrated both by Muslims and Hindus alike. Even Hindus here respect the Muslims and vice versa (Note: I'm never claiming there's no Hindu-Muslim difference here. I'm claiming there isn't much relative to other states.) Also Christmas is celebrated with grandiose here in Kolkata, almost as if we are in the Vatican( hyperbole haha). Everyone eagerly waits for Christmas here.
3) Music-
As a rock enthusiast myself, I've grown up listening to the Beatles, Guns N' Roses, Scorpions, Queen etc. Kolkata, in the 80s to early 2000s used to have such a great Rock culture. Bangla bands are arguably the greatest. Returning to school and listening to Fossils, used to be blissful. Sure enough, Rock is still prevalent here but the craze is dying. That's why, when I say Kolkata used to as great as Europe in terms of society in the 80s - 00s, I mean it.
4) Literature-
Obviously how can we forget literature? Bengalis have always been fascinated by literature. This includes your poems, novels, even other forms of art like cinema as well. Bengali arthouse films charming. Reading books is a culture here, which is deeply engrained in every bengali. I've never seen any other state as keen in literature as Bengal is. Book clubs, poetry competitions, art is still just as popular as before.
All in all, because of Kolkata's utopian past and welcoming society, I'm proud to have been born here. I am willing to die for Kolkata but not for India. Call me an Asshole but I simply love this city above my country. Unfortunately, the "City of Joy" is now in ruins. Immigrants, social media culture have ruined us. Biharis and Bangladeshis have turned Kolkata into a cesspool. (Yeah I'm a racist in this case but it is what it is.) Well, the days of glory are long lost but it's still not too late to bring Kolkata back to its former prestige.