The deal is not a "treaty", but an "executive agreement" since Biden didn't seek a congressional approval to make it. Treaties, which require the consent of two-thirds of US senators, are legally binding agreements between nations; they become part of international law. Executive agreements are concluded on the authority of the incumbent president and don't necessarily bind his successors.
President Donald Trump tore apart his predecessor Barack Obama's nuclear deal with Iran (which was not confirmed by Senate) in 2018. This illustrated the fragility of the executive agreement - which was also called "historic" in July 2015.
Recent YouGov, Yahoo News, Emerson polls show Trump leads Biden in the 2024 presidential race. Trump is also leading Biden in key battleground states which provided for Biden's victory in the 2020 elections, as per RealClearPolitics.
Even if Biden wins in 2024, his second tenure will end in 2029, meaning the fate of the 10-year accord will depend on his successor.
Treaties aren't immune to the US president's unilateral action: In 1978, President Jimmy Carter withdrew from 1954 Mutual Defense Treaty with the island of Taiwan. President George W. Bush tore apart the Anti-Ballistic Missile (ABM) Treaty with Moscow in 2002.
Last but not least, in the absence of clarification of the Constitutional Court of Ukraine, Zelensky's legitimacy as a signatory is null and void: under the nation's Constitution, the presidential tenure is limited to five years and is not subject to extension under martial law.
