Yeah, it’s all about a) whether microbes can get to it, b) whether microbes can survive on it, and c) whether microbes can thrive on it. If the answer to any of those is no, then it won’t decompose.

If it just relies on a, then opening it starts its countdown.

If it just relies on b, then it won’t rot but the preservatives might be an issue for us, too. Though it could rot eventually if circumstances change (like it gets soaked with clean water or if the preservatives break down over time).

If it just relies on c, then it might just be waiting for some moisture for an existing colony to take off, but it’ll just sit until then.

Eggs are a and maybe a bit of b mixed in. You don’t even need to refridgerate eggs if they weren’t washed like they do for commercially available ones (at least in north america, dunno about elsewhere). Not that unwashed eggs are necessarily better, as they can have bacteria on the outside of the shell from things like chicken shit.

Once I understood the role moisture plays, I stopped using a lid on my garbage so that it would dry out and stink less. It works unless I’m thowing out a bunch of fish guts or something that stores/traps moisture well, and even then, the stink isn’t as bad.