How could I highlight a block for selection?

[SoLegendary]

Given a block at position x,y,z how could I go about writing code in order to highlight it, for example by raising its apparently brightness (graphical brightness, not in-game minecraft brightness)?

For some context I have created a mod to allow for free cursor movement while still being able to pan and rotate the camera, and want to also be able to select blocks by clicking. I've already gotten the actual selection working but I can't see the block that has been selected until I implement some kind of highlighting.

EDIT: and the same for entities too

EDIT2: I'll also settle for just dynamically changing the model on runtime. If altering the model is too complex, I can just create a simple block model defined as a 'marker' block for this purpose.

EDIT3:

I asked a much better question here

Edited December 28, 2021 by SoLegendary
replaced with new question