No embargo exists (or could possibly exist) in the first place.
Linux is open source, so every patch fixing the security bug is immediately visible to everyone. There is no workaround to that by the very design how the kernel is developed. The "embargo" people talking about is the rather stupid notion that if people keep their mouth shut and not write "THIS IS A LPE" straight in the patch description, everyone can pretend vulnerability is not leaked until the "official" message in the mailing list is sent.
This approach might have been defensible before, but in LLM era, when people have automated pipelines feeding diffs straight from the mailing lists to SotA models asking to identify probable security issues fixed by those, it is both stupid and dangerous.
My (novice) understanding is that embargoes are intended to provide time to 1) develop a patch and 2) distribute the patch.
For Linux/public open source, what you said is right about 2). Once the patch is visible to anyone, it's trivial to identify exploits for unpatched systems. But 1) is still a valid use-case for embargoes for Linux vulns, right? Like, if this patch had taken a few weeks to develop before being confirmed working and published, that's potentially valid grounds for not sharing details during that time (within reason), no?