This package does not support Python 3.12. Please test it with Python 3.12 as a matter of urgency as the default will change in early June, as per message on gentoo-dev: https://www.mail-archive.com/gentoo-dev@lists.gentoo.org/msg99104.html. Please check the information provided in the tracker. Ask in #gentoo-python on IRC if need any help.
net-wireless/nanovna-server-0.6.3-r1 got Python3.12 support. See https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=4b35414690434d7807538844c8c8babf642a01d5