I've gone through quite a few cases (Ghostek, Otter etc) & the one I chose for my 11 was the Catalyst Waterproof. It's fairly hefty but has survived some grim industrial environments without any drama. Doesn't seem to suffer from echoes, condensation etc..., is 10m waterproof (allegedly), and when the rubber charging-port cover disappeared they replaced the whole thing. Not a cheap option but neither is a replacement phone.
https://catalystcase.eu/collections/catalyst-cases-for-iphone-11/products/waterproof-case-for-iphone-11?variant=31922302484527