Meeting people: Where's everyone in their 20s?

I'm 26 and became totally desocialized over the past years, because of isolation, depression and home office. I wanna meet new people, find some friends and spend more time outside. But my question is where everyone in my age is. I'm a software developer and in my company everyone is about 40+. I just wonder where I can meet people around my age. I feel a helpless about this and could use a hint.