Hey similar deal here - I returned late last year after 9 years away. Man it was a shock to see how much has changed.
First thing to be aware of - lots easier to get ganked so be careful about what you fly and where until you get your sea-legs again.
Second - resource distribution and scarcity (see forums) has impacted on most mining so it is possibly not as profitable as it once was for you unless you have an account who can get in an Orca or a Porpoise to boost you (mining command ships) or get a corp-mate to help.
If you have the skills I’d suggest missions until yu get used to the game again - most L4 pay quite a bit more than a few mil an hour, especially if you can salvage but if that’s not your thing then skill up for exploration - SOOOOO much easier than it was back when I took a break. Depending on the location and the spawns, anomalies such as relic and data sites can net you up to 20-30 mill in high-sec and up to 60-100mill in null. There is a great in-game Scanning chat channel - join it if this is your thing.
Wormholes are also great for finding sites and also getting ganked so be careful there
The last thing I want to mention was something I hadn’t thought of right away when I got back.
Before I stopped playing I had a bunch of research agents running making RP for me - now if you were like me, luckily those good little slaves (ahem) I mean agents kept on making RP whilst you were away. I came back to a billion worth of RP which was a boost but of course you have to have the cash to exchange RP for data cores and then sell on the market. Invention has no margin in it now that every man and their clone can make BPC copies and invent from them.
Working the market is still just ridiculous but you have to have obscene amounts of cash reserves to make it really profitable.
Glad to see another returning player - send me a PM if you are ever in game when I am