This is worth a read (Apple Watch accuracy tested within 0.67 BPM of benchmark chest strap): Who Has the Most Accurate Heart Rate Monitor? | Tom's Guide
I would love to use my AW4 with TR. My Tickr HR strap lasted 2 years, then bought a Tickr X which has been useless - randomly outputs HR at 10-20BPM lower than it should be on 30% of rides. Switched back to an old Garmin strap for now.