> Gary Bowser s’était retrouvé dans le

[ancient agate]

« auraient pu être » is the conditional past (could’ve been), and « le » is the neuter object pronoun, used to refer to the complement of être

‘Gary Bowser ended up in the stands in 2020 just like (how) Max Louarn and Yuanning Chen could’ve been [like Gary Bowser]’

[rustic pendant]

whats the complement of être in this case?

[ancient agate]

probably about how Gary Bowser went into the stands

the neuter object pronoun mainly refers to ideas already mentioned (Read that)