Finding area of research and people that offer PhD's in this area
If you read random papers on arXiv without having research experience or knowing how to choose, your chance to find something that awakens your interest is very little. Normally, this problem is solved by doing some research during your Master's program. You say that there are very few research opportunities for students at your university, so become active and try to get one of those few. Depending on your study program, there might also be the possibility to do a research internship for credit at a company or research center.

Even if you do not manage to find one, there should (hopefully) be a Master's Thesis at the end of the program. That should include enough research. 

At Master's level, you will do research under a supervisor that will point you to literature and guide you on how to find more. You will get a feeling of whether you actually like research, and whether you want to spend 3-5 years doing it as a doctoral candidate. You should also hopefully get a feeling of which topics you like to work on.

I am actually quite surprised at the comments from your professors: I have never heard anything along the lines of "you just kinda slip into a PhD program", and this does not look like the kind of advice a senior academic should be giving to a student. They are probably right when they say that planning two years ahead is too early, especially if you have no experience with research.