Why don’t you just buy a simple oximeter? It gives you your heart rate and oxygen level and fits any big finger. And it’s cheaper than a wrist cuff.
My nurse told me that wrist cuffs are inaccurate and either get a pressure cuff that registers your heart rate through a meter or have a nurse (if you have one) measure your heart pressure the old fashioned way .
You can get a finger oximeter cheap unless you want a fancy one with your heart rate monitor graph. It’s a little bit like an ekg graph .