Yes.

The virtual thread (VT) depends on "carrier" threads to progress. Carrier are just platform threads; the word carrier should remind you that they are under the virtual threads but not necessarily have any affinity to them.

The number of carrier threads is limited, starting at 1 per cpu core, and some extras can be allocated under special "pinning" circumstances.

Carriers do run in parallel, so some runnable VTs will progress in parallel, but not all of them.