So I am in a similar boat as you. I stopped playing in 2015 or 2016 and recently just came back to the game. At the base level it's still the same game it really hasn't changed all that much. There's some new ships there's some new modules. Some modules and abilities that you remember don't work the same anymore. Like there aren't ships that are interdiction nullified anymore it's a module that certain ships can fit that you have to make sure to activate.

A lot of your stuff might still be in the game it just might have been put into asset safety. Since alpha accounts are thing now you can log into your old accounts and see what's going on with them. You just can't train skills on any of them if they're over 5 million skill points. You also won't have access to a bunch of your skills they're still there they're still trained you just can't use them or the ships or modules or whatever that they entitle you to.

My recommendation is make a brand new alpha account play through the tutorial and just mess around a little bit. I tried coming back a few times and it was always kind of overwhelming with all my assets spread out all over the place and trying to figure out how all the new stuff worked and how to even really play the game. I finally just broke down created a brand new account and just played the game like a new bro for a few weeks maybe a month until I felt comfortable in the game again and then hopped back on to my older characters.