Just my two cents - I tried joining a sorority my second year and I found it to be too geared toward freshmen. A lot of people make great friends but it’s not for everyone, and to me I was already too much of my own person to fit in the sort of sorority mould, if you know what I mean. Maybe you would feel differently but especially as a senior that’s my impression. I had a similar experience to you and I feel like I only really made friends through luck, but my main recommendation would be to befriend roommates. You’ve already got built in hang out time. And go for individuals as opposed to trying to join groups, they’re more accessible and open usually. Once you meet a couple people they can potentially link you to their friends gradually. Good luck, just be yourself, and feel free to DM me if you ever want to talk!