June/July is a lovely time to be visiting! There are never any guarantees on the weather in western Norway, but at least you'll have lots of daylight.
I recommend spending more time in Bergen! As FlyingJoy mentioned, there are lots of very accessible hikes that start right in the city centre. And if the weather isn't on your side, you'll have far more indoors options here than elsewhere.
Instead of renting a car, you could take the train to Flåm and get
a multi-day boat pass, although you'll be wanting a car if you want to explore beyond the train/boat routes. In that case, I would suggest renting and returning in Bergen and skipping the catamaran (maybe replace it with a day trip from Sogndal). If you want to take the Flåm railway, it's always an option to leave the car in Myrdal, walk or cycle down to Flåm (4–6 hours on foot, paved roads for most of the way and very scenic) and take the train back up.