This is a wildly unrealistic viewpoint. This would assume that you somehow know the language of the client you’re building and have total knowledge over the entire codebase and can easily spot any sort of security issues or backdoors, assuming you’re using software that you yourself didn’t make (and even then).

This also completely disregards the history of vulnerability incidents like XZ Utils, the infected NPM packages of the month, and even for example CVEs that have been found to exist in Linux (a project with thousands of people working on it) for over a decade.