It's fun to play with friends, it's easier to play alone. When I go out with friends I tend to bring much better gear and die much more often. There are no solo servers but many people choose to play primarily or entirely alone anyway-- from some of your comments it seems like you've already made up your mind that there is "no point" to playing the game this way and imo that is pretty silly.

You can upgrade the secure container by completing in-game quests, this takes quite a lot of effort. Pestily has a video series where he gets the Epsilon case (size 2x4) in 14 hours, but you should expect it to a take lot longer. There is also a 2x3 Beta case which you can get from a trader and a 3x4 Kappa case which requires more or less 100%ing the game.

Hope to see you out there.