Fixing this is not going to fix the energy crisis but as uses of fossil fuels go it is among the most egregious
Like, the last time I did a back-of-the-envelope, physical spam mail was also a surprisingly large (but still tiny) fraction of US CO2 emissions. We could just stop sending spam mail, and save like a quarter percent of the US CO2. Not big, but you're also not losing anything of value.
In situations like this you prioritize... you cut the larger things that have the least value per amount of energy used.
Ending crypto mining is the easiest no-brainer in the history of energy systems.
Ending any profit-generating activity is incredibly difficult. I suspect you're not referring to ending it, but allowing it to be transferred offshore and losing the ability to regulate it. But if it's banned in the US, good luck getting every other country on earth to ban it in solidarity.
I would genuinely love to read a plan somebody has to end cryptocurrency on Earth, but I can't imagine one working even a little bit.
Attack the supply side, attack the demand side: tax it, regulate it, cap it, replace it. All of these can reduce the mining so they are all useful.
edit: to answer your idea that they will just move...
If these other places were as good or better for mining than where they are now, they'd already have moved. If you make them move to a worse mining situation, that's just proof that what you're doing is working.