MY SOLUTION
So I just spent $1,000 on these locks after hearing the exciting news that they integrated with Airbnb. After setting the first one up I quickly realized how it wasn't going to work well with guests and the obnoxious automated message. Thankfully I do use Guesty to manage my listings. Although I was trying to get away from using a channel manager due to the extra costs, I found that Guesty does exactly what you all are looking for with the automated code messaging. You're able to send messages from Guesty, through Airbnb and customize the timing and message itself. Whew! Guesty will use either the guests last 4 of their phone #, or check in/out dates whichever you set it to. When creating the message, just use the tag (Guest Phone Number - Last 4). I just set this up so as of now I can't confirm how well it works, but Guesty does a very good job with it's messaging platform, so we should be ok.
So for now I'll be keeping the channel manager just for the codes (about $35/mo just for this), but I think it's going to be worth it in order to avoid guest confusion and negative reviews. We still absolutely need Yale and Airbnb to fix this because we shouldn't need to use a separate channel manager just to send codes when there's already an integration set up.
Good luck all!
Adam