A short guide to The Boys for SPN fans who haven't watched it
The Boys is not Supernatural.
The Boys is nothing like Supernatural.
TB is not a superhero series, it's a scathing satire, which uses shock and gore as well as humour and character drama to make its points about American culture and the political landscape.
Soldier Boy is nothing like Dean. He is not a hero, he is an abusive egotistical asshole who treats his superhero posse brutally (and may even have sexually abused his male teenage sidekick) and has no redeeming features – and he is not "Dean if he was bad", the only thing he has in common with Dean is a pretty face and a pair of boots. Jensen is a superb actor, he very clearly differentiates the two roles.
There are several SPN actors who have been in the Boys since s1: Nathan Mitchell as Black Noir and Black Noir mk II (the angel Kelvin in s12); Christian Keyes as A-Train's brother Nathan (AU Michael); and of course Jim Beaver as, um, Robert Singer, a Joe Biden-ish politician. When Rob Benedict came in to play a role in s4 it was spectacular, disgusting, and hilarious - but brief, over in one episode. None of those roles had any relationship with their roles in SPN. (Except for the name of Jim's, that's a little Kripke joke.)
Talking of Kripke jokes, yes he likes his little humorous references (see Robert Singer) but I doubt if they'll be built in to the characters (see Robert Singer, who is nothing like Bobby Singer).
TB and its spinoff Gen V include several LGBTQ+ characters in a matter-of-fact way – as well as many of the peripheral characters, two of the main characters are explicitly bi (and one was in a poly relationship), mainstream biphobia is pointedly satirised, and gay sex is explicitly shown in and out of the context of loving relationships.
You cannot come up with any idea more off-the-wall or outrageous than anything TB has already done.
TB is very very dark and even the 'good guys' are morally grey at the very least. Main characters have murdered random passers-by, crashed a plane-load of people to get rid of a single passenger, exploded people's heads for politics, torn their enemy into several pieces, accidentally exploded their lover from inside their penis, been sexually assaulted and raped, had sex with octopuses etc etc etc. All shown fairly graphically. Also there are homicidal flying cows.
SPOILER ALERT: At the end of the last season, America is entering a fascist dictatorship and the only solution may be genocide by virus. Season 5 will not be a lighthearted romp.
TB is not for everyone. If you are not sure if you will like it and/or are scared to try, watching some clips or reaction videos on YT might be an easier way in.