I think it only takes about two-weeks to adjust your palette. If you stop using sweeteners for a while, you’ll soon find you don’t need them. I gave up sugar in my coffee years before I started any of this diet stuff and it was easy. I found I could better appreciate the taste without the sickly syrup in there.
It’s okay to leave strained kefir at room temperature for 24-hours to ripen. Then you can store it in the fridge. If the temperature is too high in summer, you might want to put it in the fridge sooner though.