I can go through amethyst code here: https://github.com/vitorpamplona/amethyst and check wether there’s a secret function that’s sending my nsec over a network call? Anyway I can do it for plebstr?

And yes if you’re not a dev yourself you’ll have to rely on another dev, but atleast other developers can tell you. On plebstr there’s no way for even other devs to tell you.