I'm not a user of that Bike but "Here’s what Apple’s Notes looks like on macOS 26" that looks fine.

I don't see a reason to go full transparency, no surprise that if you ask an AI to do a thing in a style it goes over the top with that style.

I've been a Bike user for a couple years, and I assume the sidebar and calendar are new additions for Bike 2.0? I've never seen them, and I couldn't find them mentioned on the website, so I believe that's the case. In my opinion, the fact that it's hard to design this well should be an indicator that these features shouldn't be added! I already have a ton of general purpose notes/calendar apps (currently on Obsidian), I don't need another. Bike should stick to its focus: Being really, really good at outlining.