This kind of thinking is wasteful. Every d20 has a finite lifespan. It was created, and it will, at some time in the future be destroyed, as all things are. That means it has a finite number of rolls in its lifetime, with an equal distribution of all possible outcomes. When you “practice roll” and get a nat 20, you have wasted one of the limited number of nat 20s that die has in it. Think of the 20s. Don’t practice roll.
That’s stupid. But obviously how the dice strikes the table impacts its balance and therefore the probability of rolling specific numbers. So we must figure out what side need to strike the table first to decrease the probability of getting an undesirable roll. Boom, I out physicsed you’re probabilities.

Louis Zocchi - The guy who made fair polyhedral dice - reckoned the problem is that polyhedral dice become unfair through the edges being rounded so they roll more easily from some sides than others and they become less than square/round

This is an old video from him about why dice suck

Louis Zocchi of GAMESCIENCE Dice at GenCon 2015

YouTube