It seems obvious that those who don't believe God's Word is true are like the Germans who likewise taught that God's Word is not truth, and who wanted the children to grow up thinking so also. They figured it would take 3 generations to fully have everyone's soul to their liking, dis-believing God's Word and instead trusting that the government wanted them to think.
Consider the large group also though, those who totally believe God created, but read some details in the scripture differently than you or me. We'd do harm to suggest they are saying God's word isn't true of course then because they believe in His Word, so our assertion would be false then. For instance, if someone thinks like I do that the 6 days are real but also representative -- thinking the 6 days are
actual days (as if recorded on video, though we can't know if they may have been shown in idealized or stylized way possibly in the vision), and further to guess that the chosen days to be shown were likely separated in time from each other -- this guessing about some
small details is not itself Truth any more than some other person guessing it was all precisely 156 hours and precisely zero time passed during verse 1 (unlike my expectation), etc.
Neither supposing about small details is the point, the Truth, but both are about some guessing, however much or little supported by whatever.
The real point of chapter 1 is to know God created
all that is, and by His design, and made it "good" and "very good", and the awe of that, and if you get those you actually are getting the real message.
But if someone thinks He created regarding such small details in a different way than I do or you do, details that are not clear in scripture, we should take great care to avoid suggesting they are saying God's Word isn't true, because in that light of their real faith, it would be a slander, of course. Obviously if they truly believe God created all that is, they already have the Truth here, regardless of trivial errors about relatively beside the point things like the time duration of verse 1 and such. Similarly for various guessing about other possible details and such so long as the person doesn't claim their own suppositions are the Truth (which claiming one's theories/ideas are themselves Truth is another kind of wrong).