Chest strap suggestion for female for martial art sports

I use a Garmin Fenix 7S watch daily to track my vitals, workouts, etc. I recently started training in martial arts (karate), and I cannot wear a watch during training. I'm looking into getting a chest strap, but I'm not exactly sure which one I should get. I want this chest strap to track my HRV and calories and help me figure out my training load. Does anyone have experience with wearing a chest strap during martial arts (karate, to be precise)? Does any female have experience with the Garmin HRM-Fit Heart Rate Chest Strap for Women that it won't fall off from a bra?