Up Strumming Question

Forgive my terminology if I’m saying this wrong, but I’m questioning myself about up strums.

From the beginner lessons, Justin said to strum downwards on all strings but just to strum up on the lower strings.

This is fine but my simple mind is wondering if this varies for chords that are only played with 4 strings, e.g. D chord vs. chords that are played with all strings, e.g. E chord?

Do I reduce the number of strings on the up strum if I’m playing chords with fewer strings on the down strum?

No not usually but you can if you want to.

The lowest strings are the E A D the term go by pitch not how close they are to the ground.
I know it seems silly but guitars are not the only stringed instrument, so going up mean higher
in pitch not direction.

What sounds best to you? You’re in the driver seat. A chord is three notes (in their proper intervals), some chord shapes have redundant notes. Nothing wrong with bass notes on the down strum and treble strings on the up. Just follow the courseware if you are a Justin student.

Thanks! It sounds ok if I catch 3 of the strings on the up strum for all chords so will do that until Justin maybe teaches me differently later in my learning.