Fitness Tracker Watch

Just finished a small road ride, was all excited because I picked up a new Garmin HRM dual chest strap. And it worked for ten seconds then stopped reading my heart beat, I took it apart, checked the battery, restarted my brand new pixel7 and it picked it up right away but no heart beat.(in Strava)

Judging by the posts in this sub, I am not the only one having issues with GoogleFit. I'll add my issue to the pile as perhaps someone has an answer or others can relate

I have a cheap fitness tracker watch off amazon. It uses an app called VeryFit to track its data. I am (sort of) able to sync it

I've been getting sharp, tight pains in my chest over the last week, making it hard to breathe. They feel like I just ran a mile even though all I did was go into the next room. It happened this morning and I felt my chest and my neck for my heartrate/ pulse but I can't feel it. My bf checked, too,

We were told the Fitbit Ace 3 could track heart rate data over time but we tried it for our child but did not see how we could get that data from it. Is there another fitness tracker watch that will do this but fit the arm of a 7yr old? It is needed for medical reasons. Thank you.