The congestion control algorithms that are applied in TCP and QUIC are actually even the same ones (e.g. Cubic, BBR, etc), so the technologies behave not too different over higher RTTs. Both will ramp up a congestion control window, which can get pretty big.

There are differences in behavior regarding what happens if loss is encountered and what exactly is retransmitted, but those still don't make QUIC radically different in terms of behavior and performance.