That is correct for ARC Prize: limited Kaggle compute (to target efficiency) and no internet (to reduce cheating).

We are also trialing a secondary leaderboard called ARC-AGI-Pub that imposes no limits or constraints. Not part of the prize today but could be in the future: https://arcprize.org/leaderboard

Using the internet would leak the test data, a big problem with ML benchmarks, and also allow communication with humans during the test.