Will adopting a kitten be okay with a 6 year old male??

Hi!! I currently have a male 6 year old (almost 7) spayed and up to date on his shots, vaccines etc. He isn’t super playful like he’ll play for a few mins but after that he isn’t interested. Trust me i’ve gotten all different kinds of toys. I don’t know with age he’s gotten less playful.

i recently took in two 8/9 week old kitten from my backyard. One is female, other is male. I’m thinking of possibly keeping one and adopting the other out. I was planning on adopting another cat this year maybe a 2-4 year old to keep him company. I work during the week so i feel bad leaving him alone.

now i have these kittens that if i don’t find a home for i’ll just keep one. (i have prospective keepers for one). I can’t tell if this will just go horribly for my current cat or if he’ll enjoy the company. Please any advice will help!!

Should i keep a kitten or just really try to find homes for both and move on to adopt an older cat?