"While there is a link to manage them within the reusable block selector, there isn’t a dedicated item within the admin menu. Unless you know the location of the management link, adding and managing them can be a bit more time-consuming."
You also have it in the main menu: https://imgur.com/a/BF8i4oh

"I noticed that I was unable to add a block inside the reusable block, it’s still a bummer that I can’t add a block inside the template for a singular purpose if a need arises"
You can, converting it to a regular block. That's logical and easy for me. Screenshot: https://imgur.com/a/REqKvf4