You don't garbage collect. Aaah game I worked on had p much every object type pre allocated at boot. Things ran until you hit a loading point. At which point you wrote new object data over the existing objects. This isn't garbage collection technically but it's the same thing. Ever wonder why some games have shit load times? Cause that's when the equivalent of gc is happening. Except like everything else in games it's coded by the engine team instead of the language implementer and so is hooked into and looks different. The game knows when it can go to shit and all of the optimizations have been done pre launch usually (if it's performant).

Basically think about how you can either build a function as recursive and leverage the stack that is built into the programming language or you can write the exact same algorithm in a for loop with a stack object and manipulate the flow of the recursion yourself. they're essentially the exact same thing however one is in complete control of the application writer and the other one is in control of the language. if you use the for lube you can actually say I'm going to run out of memory before you hit the stack limit and actually do something smart it's much harder to do this in a programming language with a built-in recursion. for instance you might approach the stacked limits in the for loop and just returned the current answer.

essentially this analogy goes for the difference between garbage collection in many games and garbage collection in garbage collected languages