Being somebody who has gotten my hands on both the iPhone 8 plus, which I used to own, an iPhone XS and an iPhone XS Max, I can definitely confirm that the speakers on the XS and XS max are superior to the 8 plus by far.
I ordered an XS Max, but my carrier accidentally sent me the XS, so after correcting their mistake, I had both an XS and XS max that I could play with until I sent the XS back.
The XS Max is an amazing phone, and I don't miss the home button at all. I appreciate having the entire screen available to me as opposed to having the bottom third being taken up by a button that isn't even real in the first place. Additionally, I haven't had any issues with Face ID, and don't know of a single blind person that has. Vo does a really good job of helping you set it up by describing how to position your face, where to move the phone, etc, and once it's set up, the phone unlocks far too quickly for Vo to give any feedback.
People always freak out about the attention setting, but come on, guys, how many sighted people do you know that can use Vo, when/if Screen Curtain is on? Also, most blind people have their speech rate really high. The majority of sighted people are not going to know what to do with your phone, even if they do somehow manage to unlock it.
As for stereo recording, yes, you can currently only record videos in stereo, but a friend of mine made a shortcut that records a video in stereo, then converts it into an audio file and uploads it to Dropbox, so you will still get an audio file in the end. Unfortunately, this does still mean increased battery drain when recording, but not much we can do about that until Apple decides to allow us to record in stereo if they ever do.
Anyway, to answer your question, I'd probably wait to see what the XR is like before purchasing. It may offer exactly what you need, and will be somewhat cheaper than the Max.
I hope this was helpful.
Mammon slept. And the beast reborn spread over the earth and its numbers grew legion. And they proclaimed the times and sacrificed crops unto the fire, with the cunning of foxes. And they built a new world in their own image as promised by the sacred words, and spoke of the beast with their children. Mammon awoke, and lo! it was naught but a follower.
from The Book of Mozilla, 11:9