How bad is variance?

I've played 20k hands at $25NL full ring.

My bankroll started at $100. I'm using ed miller SS strategy so my buyins are $5.

I played until I hit $387 and then cashed out to end up at $100.

Then I was playing some more. In one day I went from $115 to $15, and then the next day I took that $15 to $205.

I know that limit has higher variance than no limit.

I know that the ideal bankroll SHOULD be 20x the buyin. Hence I had a $100 bankroll for $5 buyins.

My question is...How bad is variance really?!?!??! Assuming that I don't really tilt (I multitable but consistently control how I play so as to not induce tilt).

Is the 20x bankroll theory enough?!? I almost had a 20x buyin swing in a day....one the negative direction and one the positive direction.