Here's another way to look at it. Is there a principal engineer in your chain of technical supervision? Does the work you do, at your current and former jobs, include a path to becoming a principal engineer?

Or another perspective. Can you be sued as an engineer? What standards would the opposing attorney or their expert witness reference to assert malpractice?

Further, could your employer be sued for allowing you to work unsupervised by a principal engineer?

In such discussion it's always useful to get back to basics regarding what engineering is and what engineers do:

https://en.wikipedia.org/wiki/Engineer

I don't see any reason not to apply the term to software. But on the other hand being a software developer is not necessarily the same as being an engineer.