>15 close friends, 50 regular contacts, 150 active acquaintances Seems like a lot. For me, it's 0 close friends, 0 regular contacts, and 0 active acquaintances. I think I simply never developed any useful social skills which would help me make and keep friends or acquaintances. I wish I had (somehow) kept in touch with at least some people I have met throughout my life. It has never been easier to stay in contact tha…
Sure you can. There are various paths to it, some outlined in sibling comments, and here’s another one: Pick up the phone and call or text some of those people you wish you had kept in contact with. Don’t have their contacts anymore? Ask someone who might or find them on social media. What do you say to them? “Hey, I was recently thinking of and felt like reaching out. How have you been doing?”.
Maybe beforehand “collect” some relevant events which have happened to your life since you last met, so you have something at the ready to keep the conversation going if you need. I’m not saying rehearse it, just have them in mind. If you need some small talk tips, see this short video.