There is no other effective strategy other than holding and/or DCA (dollar-cost averaging) for me when it comes to Bitcoin and Ethereum. Day trading would be another strategy, but that's not my forte as I am a long term thinker and not skilled in technical analysis or so.
My mistake back then was losing hope early on Bitcoin before the big bull run in 2020. I could have made a lot to be honest during that time, but it was stupid for me to let it all go. But ever since I came back and started DCA'ing on Bitcoin, there's no looking back now as long I have extra "not beer" money.
That was the problem for many people, since it didn't look like it was doing anything special, we all believed that it would be gone but in reality, there was a recovery coming around if we waited a bit more. I was lucky enough that I started accumulating before the bull run, and that gave me such a good chance in life to reset everything back to normal.
Of course, with this crisis again things are looking bad, the debts are growing, humanity is in trouble of its creation all over again but that doesn't mean that we can't make any profit. Just focus on the future when things will be alright again and make your investments accordingly and you should be fine.