If you needed oxygen during the infection, or you currently need it, and/or if you had heart problems or circulation issues, including thromboses, you must discuss the resumption of regular exercise with your doctor.
People affected by Long COVID report a feeling of weakness: physically with reduced performance (muscle weakness) and mentally with apathy and listlessness. Some can hardly walk, others have to force and overcome themselves enormously to do any activity. On the other hand, regular physical activity is important in the short, medium and long term for physical and mental health and well-being.
Thus dosage is always decisive for the success of the training: intensity and recovery time are considered as guideline values. The art is to find the balance between optimally dosed, regular physical activity and restful, restorative periods. This is the only way to increase performance and improve quality of life step by step.