You are thinking short term IMO. You are closing a core HDFC CC and it's very difficult to get a core HDFC CC later on when you already have a co-branded card. Co-branded cards get devalued statistically quite often in comparison to Core cards, plus you would close your doors to eventual climbing up the ladders to Infinnia or DCB etc etc.
Sure 1,180 is quite overwhelming, but try to make every household payment using your millennia cc first, then your fee would be waived off. Also Millennia is launched in Rupay variant now, you can convert it to Rupay and get the purpose of UPI fulfilled and increase you transaction volume on it. Even if you don't use your swiggy ltf, it isn't going to affect you much because millennia and swiggy are more or less same.
I admit cashback is directly reversed in statement in swiggy card & in millennia you have to redeem cashpoints by at least having 500 in the first place and a 59 fee. But look at the bigger picture and then decide. Also, you won't always get all the cards for ltf, even I don't have millennia ltf, using it for past 4+ years, that doesn't make the card bad. Someday if the card is devalued and the benefits are not the same, then you may close it, but as of today, even as a paid card, Millennia is an amazing CC and you can recover your fees if you use it wisely.