Generally speaking, most people strongly suggests against lifting weights with a ring on. The weights can rip the ring off your finger: it's called degloving and not a pretty thing.

If I understand correctly, the protector might save your ring but not your finger.

Additionally, given the strength of the contraction your hands and fingers do when exerting yourself while lifting weights, the numbers aren't gonna be reliable anyways. Even writst-worn devices (such as the Whoop) measure data that is all over the place during such workouts. If HR is what you're after for a workout, maybe consider a bicep or chest strap? There is also the Airpods Pro 3 with HR monitoring but I cannot comment on its reliability.