I found that the only way to get accurate readings is to wear a chest strap when I work out. I've had great results with the Garmin chest strap paired to my Fenix 6.Hiked 700vert with 30lb pack plus my 2.5gal sprayer.
Warmed up with 3 sets then
10 sets, no rest
Barbell Snatch- 85 x 5
Barbell Step Ups- 85 x 5ea
Pull Up- x 10
Knees 2 Elbows- x 5
I may make a separate thread about the Garmin watch the wife and kids got me. Accurate on runs/hikes, not worth a shit working out. It simply doesn’t read HR consistently.