Sure, that will help. But managing multiple keys is not hard. A regular password manager solves most of the way. There is no need to link keys together with a Master / Child crypto scheme.
Discussion
But currently if Iwant to take my I D across different nostr clients. I have to use same nsec don't I?
Only if you want your follows to see what your are doing with the other ID. For instance, I have another ID for DMs and another ID for my health data.
If you are on Android, you can use Amber to sign for any other app. If you are on the Web, you can use browser extensions to sign.
Master/child, or "delegates" as some call them, or "certificates" as they're called in the real world, are needed for hot/cold storage and for repudiation.
nostr:nprofile1qqsyvrp9u6p0mfur9dfdru3d853tx9mdjuhkphxuxgfwmryja7zsvhqpzamhxue69uhhv6t5daezumn0wd68yvfwvdhk6tcpz9mhxue69uhkummnw3ezuamfdejj7qgwwaehxw309ahx7uewd3hkctcscpyug why don't you stay in your lane and write some myLabel.setText code or something.
Why don't you stay in your lane and go play tic tac toe or something.