Here's what helped me in the past, to bring back the animation:
Open the WatchApp on your iPhone -> Notifications -> make sure that -> "Tap to Show Full Notification" is not enabled.
As for your speaker volume, try to clean the speaker as described in the related article:
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To clean your Apple Watch, follow these steps:
- Turn off your Apple Watch and remove it from the charger.
- If you have a leather band, remove it from your Apple Watch.
- Wipe your Apple Watch clean with a nonabrasive, lint-free cloth. If necessary, lightly dampen the cloth with fresh water. If your Apple Watch has substances or debris visible in places such as the speaker ports, you can hold your Apple Watch under lightly running, warm, fresh water until it's clean. Soaps and other cleaning products shouldn’t be used. With Apple Watch Series 10 and later, you can use a soft-bristle brush to remove debris from the speaker ports.
- Dry your Apple Watch with a nonabrasive, lint-free cloth, including the surface of the back crystal.
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copied from: How to clean your Apple Watch - Apple Support