Aside from shutting down some compressor stations that gas companies failed to properly register as essential equipment, ERCOT had almost nothing to do with NG prices.
Gas and power are intertwined but still very separate markets.
Natural gas would have gone even higher had ERCOT not shed load, so if you want to make reductionist statements about complex issues, you could say that ERCOT actually took away from the bonuses of BP gas traders who were long.
You're technically right about ERCOT's limited role in gas pricing and the regulatory distinctions. But ERCOT did have some direct failures beyond just being a scapegoat, like ignoring federal winterization warnings, the $16 billion overcharging scandal where they kept prices at maximum for two days after outages mostly ended, and poor crisis communication. Even if PUCT and the Railroad Commission should have mandated better reserves and winterization, ERCOT still mismanaged what was within their control.
They did not do their job to regulate the market. Set aside their failure to check for winterization and the complete failure of demand forecasting or execution of rolling blackouts (that ended up being uncontrolled week long power losses that literally killed people).
They had almost uncapped max wholesale prices for energy during the blackouts. At some point it had reached 10k per megawatthour! Of course companies went bankrupt, and of course BP traders held bonus parties. The taxpayers apart from these they also had to bail out the bankrupt retailers.