I’m certain cups make a difference.
My coffee cups are straight walled, 7oz cups, vitrified, stackable…like you see in conference centres/weddings/hotels…whenever I drink from more flared/rounded/thicker walled cups the coffee seems less balanced more sour?
Similar with espresso. Tradition, thick walled, rounded, egg bottomed cups don’t seem to make the coffee as sweet/balanced as some small, narrow ceramic beaker style cups a friend brought me back from holiday.
Just the other day, I was searching to find some taller, narrower cups to try against the 7oz stackables.
I gave up drinking coffee out of anything made of glass years ago.