Octavia A7 2019 , grinding sound from brakes while slowly releasing pressure , and also another sound from steering wheel when changing to right or left sound 

Welcome to the Forum.

 

Is this a car that is not getting used much and has some surface rust on the discs?

If it is from the the front MIGHT be a stone stuck between disc and shield.  Happened to me years ago on a MkII and recently on a MkIII.  Option 1 drive in reverse at top speed and hit brakes hard. Option 2 remove wheel, find stone torch is useful, poke out with screwdriver or gently pull shield away from disc to release stone.