[AppyPappy]

It’s possible with any virus or vaccine

[CatHerd]

Yes, myocarditis happen with flu:

“Acute myocarditis is a well-known complication of influenza infection.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533457/

Anyone can do an internet search on “influenza myocarditis” (without the quotation marks) and find page after page.

And yes, stroke can happen, too:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899905/

https://www.heart.org/en/news/2020/10/14/flu-and-covid-19-are-bad-enough-but-they-also-can-raise-stroke-risk