Still, we like to speak of all these companies in the same breath, but I feel like unless you worked at a few of them, it's hard to say what the actual commonalities/differences are.
I didn't get that impression. OP sounds adaptable/flexible and is willing to work on whatever team needs the most help.
If they find a manager on the container orchestration team with open headcount who wants to hire them, there isn’t much that can stop them from moving.
The last sentence is factually incorrect. During my time at FB I contributed code to the container solution, the Jenkins-equivalent, the network routing layer, the bare-metal-provisioner, the monitoring solution and even wrote a feature for the website. I identified a problem, parlayed with the owning team, and shipped that feature. This was the best part IMO about working at FB.
Also, not sure where in FAANG you had such wide scope. At FAANG either teams are mostly organized by business. For e.g. engineers working on Photos at Facebook, can't suddenly decide they want to work on implementing a feature for container orchestration at Facebook works.