Does a player know the source of an unseen force attempting [and failing] to act upon their mind? More in description

If a creature attempts to Dominate, deal save-or-suck psychic damage, or otherwise psychologically influence a PC, what do they know about the attempt? Both RAW and opinion answers acceptable, just specify what you’re giving.

Obviously the player themselves know when I ask "Make an x save".

But does the character know? Furthermore, what if it is a visible target. I don’t know if "Mind Blast" is visible, as an example, but ASSUMING it isn’t, say a PC angers a Mind Flayer, and they fail to deal damage to a PC because of a successful saving throw, does the PC know? "The Mind Flayer gives you an unsettling glare. Make an Intelligence saving throw. PC succeeds" Does the character itself know their mind was assailed in some capacity?

Lastly, suppose a PC is immune to a specific effect. I.e. being innately immune to Sleep effects.

Do they know if a creature attempted to use some magical ability to attempt to put them to sleep?