You're not supposed to wear it while you shower (soap is generally bad for any waterproof seals...). Just slap it on the charger while you shower. Or slap it on the charger when you wake up, during your usual morning routine. It's a bit of a change of paradigm from the 'charge while you sleep' that we do with phones, but you get used to it.
If you’re working out every single day, probably not. But it should absolutely be plenty to get you through a day and then you can top it off for another 10-15 mins before bed. It’ll even give you an alert informing you it needs charging to make it through the night at the appropriate time before your configured “wind down” period so you can charge right before bed.
Lower states of charge will charge faster, so 2 smaller charging sessions would result in less total time spent charging, actually.
So you’re telling me a 20 minute charge is going to get you through 24 hours with a workout every day? That just seems unlikely to me based on everything I’ve read.