Arce is the formal head of MAS, which is Morales' party. MAS won a fair election in 2020 after the "coup" in which Jeanine Anez assumed power after Morales fled the country along with the constitutional line of succession after widespread violent protests following an unprecedented 4th term election (which in turn followed his unprecedented 3rd term election, which in turn followed his unprecedented 2nd term election --- prior to Morales, successive terms were forbidden) that was broadly and, if you care what OAS says, officially deemed fraudulent. Anez, an unapologetic right-winger appointed by standard constitutional succession rules, promised elections, delivered them, and conceded power peacefully to her MAS successor, who almost immediately had her arrested and has imprisoned her ever since.

This isn't so much my take as that of the European Parliament and Human Rights Watch.