For whatever reason 1.67.4 seems to have resolved things? Maybe just the app actually restarting was the fix. I'll definitely give the user agent switch a try if I see the same issue again.
Works fine from web browser and Voyager on the same device and connection.
Trying to load my feed it just spins for as long as I leave it open, but if I minimize the app and come back it says: Network Error. Please check your internet connection and try again. It occurs on both WiFi and mobile data.
If I try to view my inbox, instance info, or web settings I additionally get an error detail link with the message: Response was not 200. Response code: 504. Url: https://lemmy.zip/api/v4/site
Pulling up that specific url in my browser fails, but with a 404 instead of a 504.
[Edit] tried logging out and logging back in, and logging in gives the same 504 from the API url
Having extensively played Star Trek Online, that is about the best you can pull in a Galaxy class. Some days I miss my time heading up the USS Turndammit.
So let's see... Shitting white means a lack of bile, pissing red means you have something wrong with the urinary tract or kidneys, and bleeding blue means you're a hermit crab.
As best as I can tell, it looks like the app being dormant for an extended period is the most likely trigger for me.