Returning player, what to do/ what to buy?

Havent played GTO in over 4 years and this was only a short span that I played it. Most of my stuff is from 2013-2018.

I do have 3 apartments, a Bunker, Facility (can't remember for what), Office and a Motorcycle Club.

What are most people doing nowadays also to earn money, don't think that rooftop rumble and Sumo are viable strats anymore.

How much do I need to invest and in which facilities?

I'm also happy about other tips.