If you haven´t found the answer I did so maybe it will help you 3 years later.
Garmin makes HRM TRI which should cover all your needs and actually doesn´t make you use watches, you can syn info from the heart rate monitor directly into garmin connect when you are finished with the session.
My solution up until now was using sportstracker app and syncing it into garmin connect. It was the best I could find for free use giving me as much info I needed and I used cheap polar heart rate monitor but!! I had to bring the phone closer to the court. HRM TRI solves this and you can keep the phone in a locker.