Hi @ldropps and welcome to Mayo Clinic Connect. Great topic to start a discussion!

There is a PDF that I have attached that I found helpful. It provides basic exercises and advice for adults who have been
severely unwell and admitted to the hospital with COVID-19. It provides
information on the following areas:
Managing breathlessness, Exercising, Managing voice issues, eating and drinking, daily living and stress
https://cdn.who.int/media/docs/default-source/ageing/support-for-rehabilitation-self-management-after-covid-19-related-illness-engf5cec00b-350b-4eb0-bc24-0704df509ae1.pdf?sfvrsn=203566f0_1&download=true#:~:text=Keep%20your%20body%20upright%20and,repeat%20on%20the%20opposite%20side.
Do you mind sharing what class it is that you took that recommended stretches?