Smart (Sports) Watch users - can you help, please?

Janika from Stoke

Does your brand of smart (sports) watch do what I need, to assist in my recovery from serious illness?
I need to buy a smart sports watch, or similar, that can monitor my heart rate all day long, (not just in “workout” mode).
It also needs to have an alert, (vibration or sound), that will warn me immediately when I go over my safe HR limit, not 10 minutes after stopping the activity.
I also need to be able to set my upper HR limit at lower than 100 beats per minute, (eg. 72 bpm).
I’ve looked at the user manuals for most smart watches online and, so far, none seem to have these capabilities.
I had a Polar watch 9 years ago that did exactly this and was ideal. The current ‘Polar Unite’ watch may do this, but I can’t tell from their user manual. No local retailer has one.
If you have a smart watch, (currently available), that you think can be set for these functions, I’d greatly appreciate your messaging me, please, so I can find out more.
Many thanks.