Hello @pickleballbob and welcome to Mayo Clinic Connect. Because of what you shared about periodic episodes after two years, I thought this discussion on covid crash may be really helpful, so you will notice I have moved your post into this discussion. Members such as @rinadbq @aae @welchllb and @sonyamagee1964 have all shared about experiences with these episodes/crashes so I hope you can find some ideas around what you are going through.

Does there seem to be any pattern just prior to or at the onset of an episode in terms of symptoms and/or environment that could be a trigger?

Hola, tengo 21 meses con long covid ay síntomas que van y vienen y otros simplemente ya son parte de mi día día. Cómo la fatiga post esfuerzo, e aprendido después de tanto tiempo que el esforzarte no ayuda a recuperarte sino que la recaída es peor. Y el ejercicio es contraproducente porque aumenta los síntomas.

Same for me, since August 2020.