How to track heart rate in BJJ with Apps

Just to make it clear, I mean tracking heart rate and calories. Seemingly no fitness app has something even close to BJJ as an option (Currently always using Boxing in Fitbit as a "replacement"/ 3 hours of rolling are counted as 320kcal 🫠)

I'm currently planning on getting a Polar H10 Chest Heart Rate Tracker.

Does anyone have any advice or experience with tracking that sort of stuff? Thanks for any replies :)