I would recommend you have someone take a look at your brakes. A soft pedal is nothing to ignore. Modern brake systems have more failure points than the systems we used to swap parts on in the past.
If you have a local independent mechanic that you trust, you would save money over going to the dealership. Just make sure it is a mechanic/garage with experience in Infiniti/Nissan vehicles. The expertise will get you a more accurate answer and save money in the long run.
If you don't have a reliable mechanic resource, and are willing to share your location, other members might be able to point you to someone they have used.
Be safe and don't wait too long.