Airpod Shape

check this link, where you can get a visualization of the differences between models

AirPods - Compare Models - Apple

Contrary to another response, I assume you're talking about the non-Pro AirPod models.. given that there is no such thing as gen3 of AirPods Pro.. gen2 vs gen3 AirPods are definitely NOT the same shape.

I loved the fit of my gen1 (original), then upgraded to gen2 (which was the same shape). But for gen3 they changed up the shape/fit. I could wear them fine for short periods, but after using them for say an 30-60 minute meeting, my ears literally hurt. I wound up selling my gen3 AirPods because of this.

If you have trouble with the fit of earbuds and you found one that fits, you may just want to stick with your gen2's. If batteries are degrading or something, just get a new pair?

Or try the AirPod Pros.. Those are great with the noise cancelling and a few different soft tip sizes are provided

Hello in_the_garden,

Thanks for reaching out to us in Apple Support Communities about the size of the AirPods Pro 2. We're happy to help by looking into this more! 

The size of the first generation AirPods Pro and the second generation are the same size, there is only a slight difference in weight. Here's a resource that will give you the specifics of the AirPods Pro 2: AirPods Pro (2nd generation) - Technical Specifications - Apple

Hope this helps.

Best Regards.