Don't know trackercontrol.
About the sandbox stuff well you don't need to know anything about it, it's just the way the Google Play services/apps are packaged and being run on GrapheneOS - they aren't running as these super system apps with massive permissions like on every proprietary Android distro. When you install them on Graphene, you as the user have full control over them including all permissions you give them (or not), they behave pretty much just like regular apps do. Which is great. But they can still function normally in that environment. This means that on every other Android distro, these run with needlessly excessive permissions. They even have device admin rights on some phones. Not cool, and just shows you how badly those default phones are configured out of the box.
About the installation process just follow the documentation it's quite detailed.
Updates are being pushed pretty much as soon as they're ready. Your phone should receive and install them automatically. You don't need to configure anything, it just works. You might sometimes be prompted to reboot to apply a new update if a reboot is required.
Well the fingerprint sensor can feel a bit overly sensitive in how you have to place your finger exactly, but it also depends a lot on how you set it up. I mean you have to position your finger like 10-15 times slightly differently each time when setting it up and so if you make full use of that and show it all possible positions then it should work fairly well. It works fairly well for me. If it doesn't work at the first try it works on the second try. For me at least. So I'm fine with it.