That is a good idea about bringing your own nsec.
Keys are generated from the recovery phrase, there is unfortunately no way to do this cryptographic process backwards.
Discussion
it's a wonderful idea and this specific detail helps me a lot.
in January I'm scheduled to have a lesson that I expect become a bulk onboarding π€£
so: I've decided to use nosta onboard method (is a bitcoin training classroom, they re familiar with recovery phrases).
since I'd like to explain the importance of NIP05, images manage through urls and LNAddress, will skip those steps (great you've done) and fulfill every part later.
will release a short visual tutorial for this, will tag you when publish.
thank you very, very much for interaction. really love it π»