When is the AI bubble expected to burst? Any forecasts or timeframes—whether short-term or long-term—being proposed with high or low confidence?

In depends on how much longer can OpenAI burn money without making a profit. See for example: https://www.wheresyoured.at/oai-business/

But we all know that "The market can stay irrational longer than you can stay solvent." So I would not bet on any short term date.

Alas, the market can stay irrational longer than I can stay solvent. :p

3 to 5 years I suspect.

That is guaranteed to happen. Not a matter of if but when. So will nVidia. ASML and TSMC will also feel the shock wave.