How to know where I stand in the job market?

I work at an early stage startup with lot of responsibilities and learnings. But I don't have an exact understanding of where I stand against other folks applying for the same position. I have 2 questions related to this:

1. How do I understand my standing in the job market? I don't have any plans of leaving my current company in near future, but you never know what can happen and I want to be prepared for such a scenario. Just to be clear, I'm not asking about interview prep, anyone can study for a few months and be interview ready. The past experience and skills picked up become the difference points in that case, and that's where my question lies.

2. I thought of applying to companies and going through the interview process to see how I fare and where I'm lacking. But my fear in this approach is that what if folks from the interviewing company reach out to my current teammates/seniors and ask for feedback? Does that even happen during the interview stage, or only during the background verification stage after offer is accepted?