Spending 4 days in Prague. What shouldn’t we miss ?

So me and my wifeare heading to Prague for 4 days, staying right in the city center, super pumped about it.

We've been looking at doing a day trip to Bohemian Switzerland NP and honestly the photos look insane. But I have no idea how to get there. Is there a bus that goes directly or do we have to rent a car? Would love to avoid renting one if possible but if it's really worth it we'd consider it.

Also more generally, 4 days, early 30s couple, we're into good food, some history, nature, and walking. What are we absolutely NOT allowed to miss? In Prague or nearby, we're open to more day trips if there's something cool around.

Bonus points if it's something slightly off the beaten path, we're not huge fans of standing in line with 500 other tourists lol