You are not alone in not being the sidebar’s default location’s greatest fan.
As you have discovered the Dropdown mode of the official Sidebar is recommended (change setting navigation menu to “Dropdown”)
This was the “classic” look for Discourse for many years and I still think it’s the best, even on desktop. Perhaps I’m a 2012 dinosaur. 
Luckily it’s otherwise functionally equivalent and in that it has really improved.