Both BTC price and M2 are highly integrated series
So the simple correlation could be a spurious regression unless you correctly treat the standard errors
I did this late last year (so its missing a few more recent months)
It shows the short-run relationship (measured by a simple linear correlation) is not statistically significant (p value of 0.51, we'd ideally like to see something under 0.05)
But other research i've done indicates there's a long term relationship and actually a "Granger-causal" relationship between m2 and btc price.

There is a relaitonship between m2 and btcprice but it's not as simple as