Those so-called lost "gospels" are not divinely inspired gospels any more so than any other secular writings of that era. God wrote the NT through the agency of divinely inspired human authors such as Paul, Peter, and John, and the Holy Spirit led the Council of Nicea to choose only those inspired books and epistles to form the canon of holy scripture. The spurious "lost gospels" are full of mistakes and contradict one another in many instances, but the "God breathed" New Testament scriptures in the writers' autographs are totally accurate in every detail and do not contradict one another.
Satan knows that without a bible in which seekers of God can have complete confidence that it is truly God's Word Christianity will fall short of His divine plan for saving lost sinners by means of their faith in His Son. So as his alloted time of liberty and demonic power grows short he has directed his primary effort at discrediting the bible as the infallible Word of God. The recent appearance of Hollywood films, TV programs, and a flood of books that purport to show that the bible is just another flawed book written by uninspired men who were prone to make errors, and if not to deliberately lie at least to exaggerate the truth, is evidence of Satan's desperation as his day of judgment before God and his subsequent 1000 years of torment in the lake of fire draws ever closer.
Speaking of that side issue, I don't know whether the lake of fire cited in the Apocalypse as Satan's place of confinement during the millennial reign of Christ on earth is an actual lake composed of some kind of burning substance, or is some other punishment that is equally horrific. But I tend to think that a spiritual being such as Satan would not be vulnerable to the physical pain of literal fire, and that a spiritual being may suffer as much or more intensely from spiritual punishment as a human in corporeal flesh would suffer in literal fire. Just my tentative opinion, and not intended as advocacy for either viewpoint.
I realize what you say is what most people believe and they believe it because they have been told to believe it by the church "authorities".
Personally I question the motives and knowledge of these "authorities" who presume to tell us what is so and warn us not to use our (God-given) intelligence to search and question.
I do not believe that the great God of this universe (and any other universes) gives one whit about all of the nonsense (imo) that is perpetually debated on these threads.
To attribute such (human) pettiness to God is laughable in my view and I cannot believe for one minute that God can be even approached with such tunnel vision.