Aggressive cat + another? Is it worth trying?

[insidior]

Hi guys!
My cat, just turned one years old and is currently living with a 15 year old cat and 13 year old Pomeranian. The cat interactions aren't great, my cat - Atlas - tends to pounce whenever possible and is always overtly playful when the 15 year old wants nothing to do with him in any capacity ever. Atlas doesn't consider the dog as a living thing lol.
As much as I play with him, he's constantly bored and just wants to go outside to hunt bugs and eat them. (Indoor cat with extreme supervision outside)

I'm going to be moving out semi soon and Atlas will be without other animals for the first time in his life and I figure he's going to be super lonely. He's lived with these two old animals that have essentially never interacted or played with him his whole life.
He has almost exclusively displayed being a d*ckhead to other cats he doesn't know and is territorial, hissing, weird guttural noises, the whole stuff. A great example of aggression is Atlas hissing and puffing on-sight for our upstairs neighbors polite, unassuming calico. With family functions where people bring their cats down for Christmas or whatever, there's usually about two and we almost never have an introductory period for the cats to relax and get to know each other, but Atlas is able to turn down aggression a little after like, 2 or 3 days. It's not really a great example for anything because cats really shouldn't just be thrown in a room together, lol.

But I'm not really sure what I can do with him?? I have so many factors with this little doofus. I obviously want the best for him and don't want to see him depressed. I try my best to be around but I'm single with a regular fulltime job, so the natural choice is to get another cat, but there's a whole new problem if he just rejects the new cat period. Is it worth trying, or just a waste of time with his already displayed aggressive behaviors? Are kittens more accepted?

I have so so many questions and factors so I'm thankful if anyone answers as all, this is a genuine problem I've been thinking about for awhile.

Here's a picture of my boi and old lady:

 

[ArtNJ]

Those aren't aggressive behaviors at all, they are just what one year olds do. It is the age of stupid enthusiasm for play, and not taking no for an answer. Totally normal, if often unfortunate, as in your case! Friendship with a kitten is as close to a guarranty as you can get in the cat world.

About the only thing you should know is that the one year old will play with the tiny kitten in stupid enthusiastic fashion, and it will scare the heck out of you. But thats fine, as long as the kitten isn't underage, you let them do their thing. Sometimes the kitten will be uncomfortable and hiss or run, but the kitten will not actually be hurt, and will come back soon enough wanting to play more. Just a bit more dramatic version of what some adult cats have -- I have an 11 pounder and an 8 pounder that have this very same dynamic even though they get along great. Sometimes the small one is made uncomfortable and will hiss and seek to disengage, but grudges are not kept and there are never injuries.

 

[insidior]

Thank you, that’s nice reassurance! I hope he mellows a bit, I hear male kittens can be a huge nuisance ‍

 

[ArtNJ]

Thank you, that’s nice reassurance! I hope he mellows a bit, I hear male kittens can be a huge nuisance ‍

Many folks say various things, and apparently there are even some studies that show some differences but I'm not sure cat genders matters much if you are going to spay/neuter before 6 months. Any time you get a kitten of either gender, there is always a chance they can be a huge nuissance. Kittens range from like an 8 to an 11 on the activity scale. But at least you don't need to worry about a kitten and one year old getting along. Kittens are the total opposite of senior cats in that regard.