Congratulations on your newly built PC! It is not mandatory to install the AMD Software: Adrenaline Edition for your RX6600 GPU to function properly. However, it is highly recommended to install it as it provides several benefits.
Firstly, the Adrenaline Edition software allows you to easily update your GPU drivers. While it is true that the graphics driver can auto-update when connected to the internet, having the software installed gives you more control over the process. You can manually check for updates, install the latest drivers, and even customize your GPU settings.
Additionally, the Adrenaline Edition software offers various features and optimizations for gaming and content creation. It includes tools like Radeon Boost, Radeon Anti-Lag, and Radeon Image Sharpening, which can enhance your gaming experience. It also provides access to AMD's graphics settings, allowing you to tweak your GPU's performance and visuals to suit your preferences.
Regarding the bugs you mentioned, it is true that sometimes software updates can introduce new issues. However, AMD generally addresses these bugs in subsequent driver updates. If you encounter any problems, you can always revert to a previous stable version or wait for a newer release that resolves the issues.
In conclusion, while it is not compulsory, installing the AMD Software: Adrenaline Edition is highly recommended for optimal performance, driver updates, and additional features for your RX6600 GPU.