FAANG co. won patent for device competitive to one I’m developing. Am I screwed?

No you are not, because you do not know for sure if the device is really competitive. Most people assume such judgments are clear and obvious but that is completely wrong. It is really about other people think, including of course the patent examiner but others too. If they think FAANG co. patent is not, or partially competitive, they you are fine.

The entire patent system is so obscure, non-obvious and surprising that I would almost NEVER assume any patent is competitive to another just that may seem to be the case at the moment.

In addition, it is basically impossible that what you have is identical to their published patent. Even if they do overlap some of your stuff will be good for another patent, based on differences and you will be in effect piggybacking on that one.

The short moral of the story is one should NEVER assume ANYTHING is obvious in the patent system. And keep in mind I am not saying it does not work.

Patents cover specific processes. You can do the same thing with another process.

For example, there is a company that patented a dust bin fullness sensor. Their patent specifically says it uses an infrared range detector,alarms via a red strobe light, and is designed to be used for the process of detecting dust levels. You could build the same device with a different range detector, or a different alarm method, or for an application other than dust bin level detection and you would be fine.