look up vagus nerve and long haul covid
try stimulating it with humming, singing, and massagers on neck and chest and see if it makes any differece
some people are using low dose naltrexone. hard to get...ask for it for weight loss or if you have an addiction.
Along with this, I would add good, systemic stretching of all major muscle groups and listening to cat purring, even if only via YouTube.
The Healing Power of a Cat’s Purr
https://pethelpful.com/cats/The-Healing-Power-of-Cat-Purrs