What is the log_reuse_wait desc for that database (in sys.databases)?

Sorry, I meant to say "have you recreated your endpoints", not checked. I saw you'd said you had already.

So you have Availability Groups in which some databases are replicating...

Do the databases succeed and fail on an AG basis or an individual database basis? Have you checked all the endpoints?

In other news, does anybody know a workaround to the issue of not being able to query otherFacsimileTelephoneNumber from AD through a linked server in SQL Server? I can get...

I came out of that interview raging and absolutely incredulous, but it gave me a good story to tell at the interview I had that afternoon, and I got that job,...

I can't log on at the moment to check my setup, but there are a couple of things you can check if you haven't already.
Run this script on the primary...

I like this rule: https://www.sqlskills.com/blogs/jonathan/how-much-memory-does-my-sql-server-actually-need/ 

In your case, assuming there's only one instance on the server and nothing much else is running on there, about 26 GB.

We have it running in an AG setup right now. I'm not trying to teach you to suck eggs, but is your application connection string definitely pointing to the listener?...

What happens when you remove the .trn files and try...

It means you can take backups on your secondary (read-only) replica instead of on the primary (read-write).

Ah, those idealistic early days!