Looking for more info on how to integrate a VPN service

Been researching a project that is developing a VPN service and thought it may be a useful service to integrate. My idea is to offer options for private browsing, similar to how the private tab can be opened through Tor.

Saw brave has both apps and extensions. When I clicked on that, it took me to the Chrome marketplace. I was wondering first, would a VPN switch work better as an app ( like how the community app worked ) or as an extension? It seems that the extensions are managed through Google, but the one I want to develop is specifically focused first on Brave. If there is any specific repos to check out or info on how to get started, please let me know.