I got into k pop a while ago and was obsessed at the time. I still listen to k pop regularly but not as much as I do other artists.
My favourite group by a MILE would be 2NE1, both because they (imo) revolutionised girl groups for the better (I.e. Girl groups can be bad ass like boy groups, rather than purely delicate and feminine) and because they were the first group I got into. I also love blackpink and 4minute as far as girl groups go, and for boy groups, Big Bang and Exo lol.
You have no idea how sad I was when I heard 2NE1 / 4minute disbanded T.T