So far the US has not rejoined Open Skies.

https://edition.cnn.com/2021/05/27/politics/open-skies-treaty-us-wont-rejoin-russia/index.html

The Biden administration will not seek to reenter the Open Skies Treaty with Russia in response to that country’s “failure to take any actions to return to compliance,” a State Department spokesperson said Thursday.

The official reason given was "due to Russian aggression".

https://responsiblestatecraft.org/2021/06/03/bidens-grounding-of-open-skies-treaty-is-folly-amid-russian-tensions/

The Biden administration had an opportunity to salvage the Treaty on Open Skies (OS), but they have chosen to let it die.

The U.S. had withdrawn from the treaty under the previous administration in November 2020, and there was a chance that Biden could have rejoined it. Last month, the State Department announced that the U.S. would not rejoin the treaty, and the Russian government has taken steps to exit the treaty as well.

Since the US did not rejoin in 2021 it has now lapsed and cannot be reentered without Congressional approval. This means it would now take more than just the President to rejoin. It would need Congress as well.