I used to have this all the time. When you suffer from anxiety and you're always stressed your body won't react to stress in the same way and it can take longer for the HR to come down again.
The answer for me was start working out quite vigorously. This forced my heart rate up over 120-140bpm twenty times or so over the period of an hour. At first it would take a long time for it to come back down, but it soon started improving. You just need to get used to your HR doing what it does.
Oh, and online sim racing is totally stressful!
I found that reflux can increase your heart rate due to the vagus nerve being stimulated.
Also, if you're worrying about your heart rate and checking that it hasn't come down as much as you thought it should, that can easily spike it another 15-20bpm for as long as you're checking.