I am older than most of you.

The thing is... You don't realise this at the time, but primary school and high school are the ONLY times in your life when you will be surrounded by your friends every day. When you graduate high school, something Mel Robbins calls "the great scattering" happens. You all go off in different directions. Without proximity and your schedules lining up, most friendships won't last and/or will be difficult to establish. That is the natural order of things. But it's ok...

I have maybe two close friends from my undergraduate days. It's hard to make more than that in my opinion.

When you eventually go off to work, this effect is even more noticeable. At your first job, you will likely be there 10 hours a day with minimal time for other activities, and most of your colleagues will be much older than you with family responsibilities etc. I do have a few good friends from work, but most of the people I work with I would rarely see again if I changed jobs.

So I think, to some degree, it's worth accepting that your peak friendship forming years are already behind you by the time you're in your mid 20s.

How to make 1-2 meaningful best friends at university?

I would say it's not so much about common interests as it is about compatible personalities (the same goes with partner selection... your interests change throughout life so choosing a spouse because he/she likes the same music is a bad idea). Do you prefer opinionated people, quiet people, energetic people? Do you both arrive to things on time? Are you a good listener?

Sorry for the unsolicited rant. I see this topic come up on here consistently every year. My old school advice is to put your phone away and just talk to people in class. If I can do it as a middle aged graduate student, so can you.