Yes, Remus Lupin has ✨top energy✨ but has it also occured you that he almost certainly does not want to be the alpha?
That boy is desperate to suppress the most dangerous, powerful parts of himself and there is no way that he does not get an insane sense of relief and pleasure at the thought that Sirius Black is the leader of their pack, not him.
Why else would Sirius have the audacity to think he could fight off Remus, as a fully grown werewolf, when he turned in POA? He was a scrawny, half-starved dog about a third of the size of an incredibly dangerous magical beast.
What could possibly make him think he could win that fight, other than the knowledge that 12 years ago, he was the alpha?
Because, as Remus John Lupin had whispered to him one night in bed, knowing that someone else could control the part of himself he'd been hiding and suppressing every minute of his life was the biggest act of love, the biggest weight anyone could ever lift from his shoulders.