I think you point out some good things.
But really, the #1 safe way to invest in cryptocurrency is actually easier than all those things:

Don't invest more than you are willing to lose.

You need to see your investment as something you can completely lose.
It's not being negative, it's being practical.
If you see it that way, you will be much more smart in how much and when you invest.

and then, the #2 safest way to invest in crypto is to immediately pay yourself back as fast as you can.
If you invest $1000 dollars, your first goal should be to earn $1000 back and have some left over to trade more.
That way, after that, everything is a gain.