Analyzing CS2's sub-tick implementation:
In CS:GO, inputs were quantized to 64 or 128 tick boundaries. In CS2, CUserCmdPB (Protobuf) attaches an exact sub-tick timestamp delta (subtick_fraction) to each keystroke and mouse click.
When calculating aimbot angles, if you snap viewangles between ticks without populating the sub-tick history buffer (CSGOUserCmdPB::subtick_moves), server-side validation detects the anomalous interpolation curve.