I have noticed since the February 2024 outage that ATT networks seem to be 10-20ms more latent than they used to be before that regardless of where I am in the country and what equipment I am using. I used to get 20-40ms with no problem beforehand just like the other carriers and now I’m doing well to get under 50ms from them since the outage. Both other carriers handily deliver better latency at the moment and also better jitter most times as well even if ATT has better reception. It has made ATT less compelling when trying to utilize SF because of this. Am I only one?
I found this chart that might help you. If your Latency isn’t falling within these ranges I would contact your carrier to see what is going on.