The best charging practice for iPhone battery

I see several recommendations on battery life, but I can't find the answer to one question:

Is it better to leave the phone on the charger on my desk all day, or let it drain during the day and fully charge it at night?

When storing the battery longterm, Apple recommends having it partially charged, like 50% to 80%, but not fully charged and not almost empty. If it's fully charged or empty longterm it will cause damage to battery life.

But what's the best practice on a daily basis? Keep it fully charged all day except when using it, or will the battery last longer if I let it drain to 40% or 50% during the day, then charge it once at night? Is it better to keep the battery between 30% and 80%, like the Tesla?