That’s absolutely false. I have personally tested a range of different steep times and the difference in taste is obvious. If you can’t taste the difference your taste buds must be fried or something.

Pressing down on the piston does not provide a meaningful amount of pressure; this has been proven by people instrumenting aeropresses which provide more back pressure than an espresso. Extraction is objectively time dependent, it has been extensively discussed and really isn’t up for debate at all.