is this a good czechia itinerary?

so I am going to czechia in septemeber and trying to map out my trip. I want to spend a good amount of time in prague but want to see other places too. I think I have a pretty good itinerary but would love any feedback. trying to not be too busy traveling around so it's a relaxing vacation but also would like to see and do a lot while I'm there!

septemeber 11th- fly from california to prague

12th-14th- explore in prague

15th- pick up rental car and dive to bohemian switzerland and spend the day there and stay overnight

16th- hike in bohemian switzerland

17th- drive back to prague and return car spend remainder of the day in prague

18th- day trip to kutná hora to explore and visit st. barbara's church and the ossuary

19th-train to ceský krumlov and spend day exploring there. stay overnight.

20th- train to brno and spend the day there

21st- go see moravian karst and return to brno in the evening

22nd- back to prague

23rd- fly home

ps would love any recommendations of cool things to see/do/eat in these places that aren't the usual big tourist spots