To complement a full-time job, it's always a good idea to have a side gig. Trading cryptocurrency or forex, especially during a bearish run, is a good alternative, but combining the two will take a lot of time. Investing in cryptocurrencies, especially during a bearish run, is another good option, though it is better for a long-term perspective that can guarantee a reasonable profit, setting up a side gig.
~snip~
Side job or any available venue to earn extra may allow you to improve your financial capability, but it's in need
for you in also budget yourself and
try saving and not to overspend your extra earnings.
It's on you, if how you will manage your extra income, more on self-control and wise choices of investment.
I agree that we need to do saving and not overspend on something first, many people tend to invest their money or trade their money to get more income but in my opinion, if we want to reach financial stability we need to not overspend on something that we actually don't need. Since investing and trading has a risk both of them won't guarantee our side income.