How can I make an informed decision on whether to do a PhD in engineering or not?
Does your uni have guidance councilors? Probably you can easily get an appointment. Maybe they will be glib about it, but it can be helpful data.

At least two aspects: What job can you get that you could not get now? And is it worth while spending at least 4 years, maybe more, getting the degree to get that job? If you want to be an academic then PhD is probably indicated. If you want to be in industry then consider going no farther than the master's degree. Or stopping at the bachelor's. 

Carefully scope out what it will cost you to get the PhD. Not just your university fees. But to live for that time. Scope out what scholarships you can get. NOTE! You must apply for most such scholarships. You do NOT get automatically considered for the bulk of them. Ask the support staff in your uni and the uni you are considering going to what scholarships exist and how to apply. Find out what it costs to live in the city you are considering. Find out if the uni will give you work while you are a grad student. Or if you can maybe get contract work in the industry relevant to your study subject.

Send out a few resumes to potential employers. Maybe the offered starting salary will turn your head. And at worst, you may get some interviews that will be good practice. And polishing your resume is good practice also. Tune it to the potential employer.

The difference between what you could earn in 4 years, and the payments you would need to make, will be substantial. And you will then be 4 years ahead for the rest of your job life.

Many academic areas have some equivalent of "Physics Today" which is the one for my area. Such magazines give stuff that is along the lines of "proff so-and-so has just finished big-name-project blah-de-blah, isn't it pretty?" And they have a ton of adverts for various things somewhat related to the subject.

But importantly, once per year they have lists of PhD students who recently graduated, and where they went.  So, what you should do is have a look at where grads from a school you are interested in eventually went. And if those destinations seem good to you, great, go ahead. If they bore you or worse, look elsewhere. One of my cohort in PhD went to work at the Science Center, and now spends his time teaching high school students about static electricity. After a PhD in particle physics. Sigh.

You may need to ask the librarian at your university what the correct magazine is to check, and how to find it. And you may be able to get lots of back issues on-line, free or nearly free.