I play too much CSGO, I found that a ping above 120 makes play too hard. Thankfully a change in ISP/technology dropped my ping by about 80.
Were you switching from dialup to high-speed internet? The latency numbers sound about right for dialup to a local server - if memory serves from the early 2000s.
No, ADSL to FTTC. Same POTS twisted copper pair over telegraph poles from cabinet to internal master socket.