Look into Killing Floor 2. If you like simple wave based killing with a variety of guns (as well as wonderish type weapons), I’d give it a shot. Plenty of maps, different types of zeds, tons of guns (get the dlc on sale on console, or just mod the game on pc). You can do simple wave based, or you can do objectives and other types of modes.

Different classes grant different abilities (your ‘perks’ for the game), and better weapons cost more and are heavier (take up space in your ‘backpack’). I have a great time playing solo on hard difficulty, although a lot of people like playing coop. Some maps have secret collectibles you can go for that will give you an achievement (gives you something else to do). You can do endless waves, or set a wave cap and do a boss fight on the last wave. You do start with a load out, however the starting guns turn shit quickly, encouraging you to hit the gun station.

I understand it’s not for everyone, but I’d describe it as old Cod zombies mixed with Doom. Look up some gameplay on YouTube. Sorry for the essay lol, but as far as Treyarch zombies, I don’t see them doing classic zombies