the level of control that dumbledore has (& exercises, mostly if not entirely consciously) over r&s's relationship is insane to me honestly.
like sending r&s off on missions that dont line up w each other so they dont see each other often and start to suspect one another. so they become loyal to dumbledore rather than to each other.
and then denying sirius a trialβwe dont know canonically how much involvement dumbledore had w this, but I highly doubt that a bunch of 18β21 yos managed to outsmart dumbledore. theres no way that dumbledore didnt at least have an inkling that j&l switched secret keepers, if not knowing outright that it was peter. dumbledore was on the wizengamot and didnt push for a trial? he even testified by providing proof that sirius was j&l's secret keeper. and when harry told dumbledore about sirius's innocence, dumbledore believed harry immediately. almost as though he already knew.
and then dumbledore, who has been ignoring remus for 12 years and leaving him to fend for himself (again, this is fanon but implied in canon and just... the most reasonable assumption imo), conveniently decides to ask remus to be the dada professor right after sirius escapes. because dumbledore wants to keep an eye on remus; because he wants to ensure he can control remus; because he can use remus to deal with sirius. and, who knows, perhaps he even had the intention of r&s reuniting at hogwarts too.
and it's dumbledore who tells sirius to lie low at lupin's, dumbledore who orders sirius to stay cooped up in 12 grimmauld place, etc etc.
ive always thought there was such a cosmic fatality to the story of r&sβthey cant escape each other, and are doomed to return to each other and wound each other in an unbreakable cycle. it's almost as though their story was planned and orchestrated. i normally just attribute this to a vague concept of Fate (which does canonically exist in some form in hp, with divination and prophecies and whatnot), but if you want to interpret it as an actual being consciously controlling r&s's relationship to make it a tragedy... well, dumbledore's right there.