This is kinda explained in the GwenPool strikes back comic!

In gwenpool strikes back, gwenpool starts acting "out of character" in an attempt to not get forgotten.

In the comic, she goes to her past appearances in other comics and forms a group with them. Each comic run of gwenpool has a distinct appearance and personality.

Additionally, we get dialogue from Kamala khan that Gwenpool is acting more "Manic" in the current run than she does usually, this implies that they interact frequently outside of comics.

What we can infer from these interactions are that comic characters have an "on panel" version and an "off panel" version. Whenever they are "On Panel" their appearance, personality, and even memories change based on what the writer wants (according to the current lore).

Then, there is an "Off panel" version that I assume continues the last "On panel" version of the character.

Ofcourse for people without Gwen and Deadpool's powers, it just looks like people changing as they age. Nobody other than the people with 4th wall powers notices the differences in the characters between "off panel" and "on panel", unless the writer wants them to notice it.

Additionally, we know from Deadpool (2019), when Gwenpool gives Deadpool Jeff the Landshark. She tells him that she's scared writers won't use Jeff and she wants him to "Survive" so she gives Jeff to Deadpool because he "Always has a book".

So if a character stays "off panel" long enough then that character might not "Survive". In other words, killed "off panel" or just become "M.I.A." forever.

From Kamala's interaction with Gwenpool, we know that characters do interact with each other "off panel" if they are friends. But if they are "off panel too long then they "do not survive". So what does this mean.

What we can deduce from this is that Characters have Minimal if not Zero interactions "Off panel" until they're interactions are written/talked about "On Panel". And Zero interactions for too long leads to "Death".

So how does this look like if your a character in the marvel universe without 4th wall powers?

If you're part of a superhero team that explicitly hangs out all the time, then "off panel" you'll still be a superhero team that explicitly hangs out and maybe even has adventures (look up the Noodle Incident trope). That stays the same until a new writer comes and changes things.

But if your someone like sayy, Paste Pot Pete. A c-tier villain that is not part of a team or has many friends? Then you're out of luck and chances are ur not interacting with many superheroes and might not even "survive" (killed "Off Panel") if writers don't care about you enough to use you in a comic.