ATH is usually a strength signal, not overheating.

Intuition says buying highs is late. In reality, it’s often the opposite. Entries at all-time highs tend to perform no worse, and sometimes better, than random timing.
The uncomfortable part is that the best entries rarely feel good. They happen when everything already looks like it pumped.
I stopped treating ATH as an automatic reversal. Markets spend a lot of time near highs. Once the trend is real, those highs often turn into support.