What does “having a meltdown” mean to you?

I (36M) have been catching up, late to the diagnosis game, but understanding myself through an AuDHD lens has been incredibly helpful to getting myself on the way to living intentionally aligned with the way my brain works. One point that has never made much sense as far as my lived experience is concerned is that I wouldn’t say I’ve experienced ‘meltdowns’ in any sort of classic sense. Now, as I’m living and communicating more intentionally to varying results, I am experiencing VERY classic meltdown behaviors. Mostly lashing out physically when I feel like I’m not being heard or what I identify as clear communication isn’t being respected. It’s often as if my brain is processing the physical behavior in an observational and encouraging way, but it feels like someone else is doing the physical behavior. Is this consistent with anyone else’s experience? I’d love to hear your experience.