What Ever you do it now just get better on this you don't need to search for things what to start just improve things what you have now.
I don't understand what you are talking about, how can someone become rich with a lot of money in a side job, as far as I know crypto is not a job, how do you say crypto is a side job, what do you mean.
If you mean trading, investing in crypto, that's not a job, if you enter the world of crypto, it means you are ready to face the risk of losing, not gaining wealth or economics, not everyone will understand trading or investing, so those who have the knowledge cando it all.
If you want to be rich, open your own business or business, not a side job, by doing business you will determine your own destiny to become rich, you have control in mobilizing your own finances to become rich or poor.
Too many people in the world worked for a while, and while working, also invested in crypto on the side and I believe that's what he is talking about? Not entirely sure to be fair, that's what I assumed, and it's not a job, it's investment so you are right that we can't call it a side job but not everyone speaks English like it's their native language so some people may make those kind of mistakes.
It's true that if you have a normal work, like you go 9 am every day, get out at 5pm every day, that kind of job, then yeah I agree that having crypto investments on the side, check them out when you get home before dinner, is the best method. Let's say you get out of your job at 5pm, at home by 5:30, and eat dinner by 7 pm, there is 1.5 hours left for you before dinner, then you can spend that checking out crypto and making investments. You can keep doing it after dinner too, but I think 1 hour give or take everyday is enough, no need to be obsessed about it.