He did. Trump issued an executive order to harden the transformers but once Biden got in, he reversed Trump’s order.
From March 10, 2021
https://www.heritage.org/cybersecurity/commentary/could-china-hack-our-electric-grid-joe-biden-just-made-it-easier
The recent winter storm that crashed Texas’s electric grid brought untold suffering to tens of millions within the state. That calamity is but a small taste of the potential suffering that could be visited upon hundreds of millions by power breakdowns deliberately caused by imported equipment within the grid itself.
Secret “back doors” in transformers and generators imported from such adversaries as China and Russia could enable those countries to shut down the entire national electric grid, throwing the entire country into chaos.
Recognizing this threat, the Trump administration issued Executive Order 13929, declaring a national emergency with respect to the nation’s electric grid and prohibiting the acquisition or installation of “any bulk-power electric equipment designed, developed, manufactured, or supplied, by persons owned by, controlled by, or subject to the jurisdiction of such foreign adversaries.” In addition to China and Russia, the order identified North Korea, Iran, Cuba and Venezuela as “foreign adversaries.”
The order was a shrewd and timely response to a growing threat. Unfortunately, that Executive Order has now been suspended.