macOS 11 Big Sur does many things right and after a bit of getting used to, the visual style really grows on you. The transparent menu bar, however, is a bit of a legibility nightmare and something I could not live with. So I developed Boring Old Menu Bar to bring the “perfectly fine” macOS Catalina menu bar to macOS 11 Big Sur.
https://www.publicspace.net/BoringOldMenuBar
It’s a $10/one-time purchase (which seems like a lot in these Mac App Store days), but there’s a 14-day trial to see if you like it that much.
Personally, I agree that I like Big Sur’s UI changes except the transparent menu bar, and I don’t want to enable “Reduce Transparency” to fix it.