Knowledge about how the other side of the fence works doesn't suddenly make a full-stack engineer. I'm sure if we actually came up with a ratio (80/20 vs 50/50) of work it would provide a clearer understanding about when a person is FE, BE, or FE/BE. Alternatively, we could look at the type of work the individual is doing. For example, in your role are you going to be an architect doing solutions for the back-end?
It’s not just knowledge, I can actually do all the work, and yes, I could design solutions. It’s just that my real deep knowledge would be FE. But I consider myself full stack because I can do both sides without a problem.
In my team I’m just the only FE, so naturally most of that work falls on me. There are months where I only did BE stories.