Media Encoder "Failed" on almost every video

I wish I could be more specific about the issues I'm having with Media Encoder - most people's problems I've seen thus far have been with a single project, and a diagnosed and repeatable problem. Not so lucky in my case, but here's the situation:

Media Encoder fails on renders. It fails on all my projects at this point. This started about 2 weeks ago. I create my sequences based on my footage settings. After that, it's a combination of Adjustment layers with Lumetri colour for grading, occasionally graphic layers, but not always. Sometimes using type, not always. Sometimes with After Effects sequences through media link, but not always. If I have only one sequence rendering it fails. If I have multiple sequences, the first one fails, then ME rapidly runs through the balance of sequences and fails them all in about 6 seconds. Again that's with or without any of the variations to my timelines above. That's also across at least 5 different projects, using 3 different camera sources and 3 different audio sources. These combinations and variations from these same cameras and audio sources have all rendered no problems at all previously to a couple weeks ago. If I render the projects directly from Premiere, they render fine, using the same settings. If I restart, then ME will mostly render them fine, but not every time.

I've updated the app recently. I've re-set the app preferences. I've cleared the media cache, by using the preferences method, and manually clearing the "common > media cache" folders. I'm on Windows 10.

Frustrated, as I'm not doing anything repeatedly the same, and assuming I haven't spontaneously forgotten how to do post properly, I have no idea where to even look for the issues. Anyone have any ideas?