As already mentioned I assume that the delay in the release of NOS 2.5.3 for NP2 is due to an accurate bugfix, personally a delay of a week in the release of an update does not seem so scandalous to me (considering that Nothing is still a startup and that the The update does not fix any critical stability or security issues. The fact that NOS 2.5.3 has been released for NP1 (with a much more limited changelog) makes me think that within a couple of days it will also be released for NP2.
Hopefully with an excellent bugfix, like for NP2a