There's a big difference between central characters and minor characters. Here's what I mean:
1. Getting punched in the face
Minor character collapses unconscious in a heap, never bothers anyone ever again.
Major character rides the savage blow, comes back for more. And more. No matter how often he's hit, he keeps on going even though he's obviously going to be battered to death. Then, just when you think he's finished, he swings a hay maker of his own and his assailant collapses unconscious in a heap and never bothers anyone ever again.
2. Getting shot
Minor character dies without fuss from a single wound.
Major character staggers slightly, looks down at the blood seeping from his shirt then carries on regardless. May take several more bullets with similar minor effect. By the next scene all traces of injury have gone and he's restored to full fitness.
Minor characters rarely speak and if they do it's usually monosyllabic.
Major characters can't stop spouting on. They have an opinion about everything and a back story that they can't resist constant references to. Their speech defines them, makes them real and tells us what we should feel about them.
Minor characters, like farm animals, don't usually have names. The reader/viewer has enough information to take in without having to memorise names that may never be heard of again.
Major characters have memorable, carefully chosen, names. Like Bilbo Baggins and Lyra Belacqua. Or Milo Minderbender. Or even Lady 3Jane Marie-France Tessier-Ashpool.
I suppose you're getting the drift, now. But, apart from the potential amusement, why am I pointing this out? I as usual with me, it's a observation that might help my writing. It's important for me to remember to make a clear differentiation between major and minor characters so that readers get a helpful steer on who to engage with and who to ignore. Otherwise, I risk overloading them with information and maybe get myself confused as well.
But how many major characters are allowed? As many as I can keep up with, I suppose. It's a bit like spinning plates, if you're old enough to get the reference. For the younger readers I should explain that it was once considered top class entertainment to watch a man keeping plates balanced on thin poles by keeping them spinning. The audience would gasp with excitement at such a wonderful spectacle, I'm surprised that nobody has been on Britain's Got Talent with such an act. Problem with spinning plates is the ones that fall off and spoil the trick. If a character or plate is going to smash on the ground I'd advise making it happen rather than watching helplessly.
Did you recognise the names I used as examples? In case you didn't they came from The Hobbit, His Dark Materials, Catch 22 and Neuromancer. If there's any of these you've not read I suggest you stop what you're doing and get reading.