Recently, I've seen people using the supply curve of stablecoins to justify ETF inflows.

In other words, there is a correlation, but don't mistake it for causation.
An increase in stablecoins might just be OTC channels, reserve preparation, or waiting for withdrawals, not necessarily "signaling a rally."
I still prefer to look at on-chain turnover rates; if the activity isn't there, no matter how big the narrative, it can easily become a false alarm.

Recently, in a certain region, tax hikes and regulatory signals have been tightening and loosening, and deposit and withdrawal expectations have been changing accordingly.
You'll find that many funds are hesitating, not rushing in.
Anyway, I only follow my take-profit levels; once hit, I exit.
Remaining calm and exiting is much more comfortable than guessing macro trends.