Hi, and welcome to the Apple community!
Apologies for the long wait you have had, for a reply.
Am no expert in this area, yet your question deserves some response.
Re: "AirPods2 hearing Aid volume : How do I adjust the volume of someone talking to me?"
You can: Adjust amplification level, balance and more in AirPods Pro settings
You can adjust settings such as amplification level (how much your AirPods amplify the sound around you), left-right balance, tone and Conversation Boost on iPhone, iPad or Mac (requires macOS Sequoia 15.1 or later). For quick access to settings, you can use Control Centre to adjust settings.
- With your AirPods in your ears and connected to your paired device:
- On iPhone or iPad, go to Settings > your AirPods, then tap Hearing Assistance under Hearing Health.
- Tap or click Adjustments.
- To adjust how much your AirPods amplify the sound around you, drag the Amplification slider to the right or left. You can also adjust amplification from Control Centre. The volume buttons on your device don’t adjust the Hearing Aid amplification level (but do adjust the volume of media playing on your device).
- To increase or decrease amplification levels by swiping up or down on the Touch controls of your AirPods, turn on Swipe to Control Amplification. This feature only works when in Transparency mode and no media is playing on your paired device.
- To adjust the balance between the left and right AirPods, drag the Balance slider left or right.
- To make the sound amplified by your AirPods brighter, drag the Tone slider to the right. For a darker, less bright tone, drag the slider to the left.
- To decrease the amount of noise in your environment picked up by your AirPods, such as fan noise or road noise, drag the Ambient Noise Reduction slider to the right. This can help improve intelligibility in noisier environments.
When you change the settings for your AirPods Pro 2, the settings carry over to your other devices. If you have multiple sets of AirPods, you have to set up each set separately."
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"Use Conversation Boost with Hearing Aid
To improve intelligibility in a face-to-face conversation, turn on Conversation Boost. Conversation Boost is best for one-to-one conversations when the other person is directly in front of you.
- On iPhone or iPad, go to Settings > your AirPods, tap Hearing Assistance under Hearing Health, tap Adjustments, then turn on Conversation Boost.
- On Mac, choose Apple menu > System Settings, click your AirPods in the left sidebar, then click Hearing Health. Click Adjustments under Hearing Aid, then turn on Conversation Boost.
You can also turn Conversation Boost on or off in Control Centre on your iPhone or iPad.
About Noise Control modes with Hearing Aid
The Hearing Aid feature only amplifies sounds in your environment when you’re in Transparency mode.
Media Assist makes adjustments to improve the clarity of music, video and calls across all noise control modes."
Above comes from : Use the Hearing Aid feature on your AirPods Pro 2 - Apple Support
NB: There is a lot more info. in that article (link above) such as controlling audio from Control Centre ... and more.
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If you haven't already tried it:
Wondering if using the "Live Listen" feature may be helpful to you when listening to people in some circumstances
See how to: Use Live Listen with AirPods or Beats - Apple Support
All the best :-)