CS2 is mostly 64 tick from what I understand. The "sub-tick" stuff is timestamping actions that happen on a local frame before the next tick. So in theory the client feels perfectly responsive and the server can adjust for the delta between your frame and the tick.

In practice it seems to have been an implementation nightmare because they've regularly shipped both bugs and fixes for the "sub-tick" system.

The netcode in CS2 is generally much worse than CSGO or other source games. The game transmits way more data for each tick and they disabled snapshot buffering by default. Meaning that way more players are experiencing jank when their network inevitably drops packets.