high latency

I've had Xfinity internet for years. No issues. Then, starting last summer, I believe, they were "working on the lines". Since the summer of 2025, my latency is so high, online gaming is non existent. It NEVER went over 19ms until they were "working on the lines". Now, I have a constant 35-40 ms with constant spikes into the 500s. Absolutely terrible. Unusable. Can someone help me? Please. I even paid extra for Xfinity Pro. Didn't help.