Fenix hasn’t shown training status since April 6. It says “do two runs outside to update status” I’ve had over 20 runs since it stopped recording.

Only updates the status with run activity, not works with trail run or another activity, and also needs and HR band. I hope this helps you

It has a built in heart rate monitor why would you need to have an additional device to measure heart rate? I’ve also had the watch two years with consistent data but, never used a chest strap.

This is my last 4. Normally do 3-4 runs a week.

Hm, the runs seem to be OK, but mostly at the same pace.

Some thoughts
1. try to install the last SW at the watch and restart it after installation
2. try to install the last SW at the phone and restart it after installation
3. check the user settings (weight, height, age, activity level, HR zones)
4. try to run with a greater variety in pace, i.e. make very slow runs and also make maximum runs. So that the SW can better calibrate your performance.