I'm okay with my character being fourth-walled if I'm an LCW and the player doing so doesn't hit my character with the whole "you're fake fake fake not real and I know all of your deep secrets/emotional trauma and I'm putting you on blast haha". The characters that I've played who've been fourth-walled like this tend to be known in their universe and also know about the multiverse concept so it was weird, but not mind-breaking.

With one of my guys it was actually good for him, because he sometimes felt very alone in the setting, so he ended up making close friends with the fourth-waller (who also curbed the meta commentary and acted normal).

On the flip side, there was a fourth-walling character in a recent game that liked to unload details about the fictional characters they knew all over the network, which seemed really tasteless. While they got permission to know these characters, it seemed like they were really making a mile out of that inch, for comedy and as a way to make themselves important. It meant the fourth-walled characters couldn't get to know others organically, because Snappy Stu already told everyone.

So yeah, don't do that.