Note: The home link for the community above should be lemmy.ml/c/ps5 but it's not working atm, and that's a separate issue I'm trying to fix over on Lemmy support.
This is an issue with lemmy.ml, not lemmy.one. Lemmy servers are responsible for sending information out to other servers, lemmy.one is not responsible for pulling information in.
If lemmy.ml is not federating your community posts or your community there is broken entirely (which it sort of looks like...) then they have to fix that, or you have to rebuild a new community on an instance which isn't broken.
Are we observing lemmy.ml having slow-downs or congestion problems?
Absolutely, even now I just opened lemmy.ml in a web browser, and the page half-loaded without any styling. Their instance is not functioning reliably in general.