The poll was conducted by Ipsos. 538 rates Ipsos a B- for its US election polling. I imagine this poll wasn't perfect but was run by professionals who knew what they were doing.
I can't find an English language page for the poll but here's a Portuguese one: https://www.poder360.com.br/eleicoes/lula-venceria-bolsonaro-no-2o-turno-por-58-a-25-diz-pesquisa-ipsos/
Even US lib media is reporting on this poll, indicating it's at least credible: https://www.bloomberg.com/news/articles/2021-07-05/bolsonaro-s-popularity-hits-lowest-point-amid-vaccine-scandal
The poll was conducted by Ipsos. 538 rates Ipsos a B- for its US election polling. I imagine this poll wasn't perfect but was run by professionals who knew what they were doing.
I can't find an English language page for the poll but here's a Portuguese one: https://www.poder360.com.br/eleicoes/lula-venceria-bolsonaro-no-2o-turno-por-58-a-25-diz-pesquisa-ipsos/
Even US lib media is reporting on this poll, indicating it's at least credible: https://www.bloomberg.com/news/articles/2021-07-05/bolsonaro-s-popularity-hits-lowest-point-amid-vaccine-scandal