I just tried fingerprintjs. Got different IDs on the same browser in normal & incognito mode. Doesn't seem like any help at all.
Known issue apparently: https://github.com/fingerprintjs/fingerprintjs/issues/1088
You are supposed to get a different ID in incognito.
Their Pro version returns the same fingerprint in incognito. That's the point, right, to get the fingerprint of the user agent independently of incognito or not.