Ok so slightly different angle here..
I have had Covid pre vaccine (March 2020) and got myocarditis confirmed via MRI scan. It was pretty bad, in that it limited me significantly for 6 months (also had long covid fatigue) but the heart pain was very scary and nobody believed it could be covid caused at that point until finally a decent cardiologist intervened. I was 37 at the time, very fit. Anyway my DD who was 10, I think also had myocarditis from Covid. I can't be sure but her symptoms matched mine identically for 3 months only I got an MRI and she didn't. Her's was milder but significantly reduced her ability to do anything active. She is usually super sporty.
Fast forward many months, myocarditis resolved for me but i then had 2 x pfizer jabs, first one mostly ok, slight return of heart pain but i was so terrified of having Covid again I went for a second. Myocarditis returned significantly, showed on another MRI scan 5 months AFTER the vaccine as still present and in a 'new area' from previous scan so it can really have been the vaccine as i hadn't been ill or had covid again. I have now been given an exemption and told no more vaccines.
There is absolutely no chance my DD is having the vaccine (unless she wants it at 16). She is 12 now. We have both had Covid since (her unvaxxed but obviously not naive to it), both ill but no flare of myocarditis.
Clearly this is one person talking here so this is not me saying this WILL happen to your child but as a parent who has a.) had myocarditis and b.) likely seen her daughter have it i won't be risking it. It was very scary to see her with 'heart pain' repeatedly over several months. Thankfully now she is recovered.
The risk of long covid is a worry for kids, my DD had that too but i still won't risk it. Has your DC had Covid OP? If she has I would be even less inclined to vaccinate personally.