I also have this feeling about the suttas, but more specifically directed towards references of human beings living for thousands of years. Tbh, there is still a certain cognitive dissonance arising from time to time, like “this sounds so incorrect” or “isn’t this type of mistake exactly what we would expect from a wrong religion?” But I still think there are better reasons to follow than to abandon Buddhism.
Because he taught according to his insight, he couldn’t teach wrong facts. If he did teach wrong things, then this brings into question the whole Dhamma since all teachings derive from the same thing: insight into reality.
As @stu said, delusion refers to not understanding the nature of reality, but I think it’s still possible for him to believe in wrong things. In fact, there are examples in the suttas that show mistakes made by the Buddha. However, these are not derived from his insight per se. I think these are simply worldly errors, like thinking a monk understood a lesson correctly when he actually didn’t.
When the suttas refer to the Buddha’s knowledge of past lives, they usually show as if he could remember past lives as many times as he wanted, but not as if it was constant knowledge in the back of his mind.
whenever I want, I recollect my many kinds of past lives. That is: one, two, three, four, five, ten, twenty, thirty, forty, fifty, a hundred, a thousand, a hundred thousand rebirths; many eons of the world contracting, many eons of the world expanding, many eons of the world contracting and expanding. I remember: ‘There, I was named this, my clan was that, I looked like this, and that was my food. This was how I felt pleasure and pain, and that was how my life ended. When I passed away from that place I was reborn somewhere else. There, too, I was named this, my clan was that, I looked like this, and that was my food. This was how I felt pleasure and pain, and that was how my life ended. When I passed away from that place I was reborn here.’ And so I recollect my many kinds of past lives, with features and details.
MN 71
To me, it sounds like he didn’t remember ALL his past lives, but a significantly large number of them, even because recollecting literally all past lives would take infinitely long.
I think these two are almost enough to explain weird claims made in the suttas. However, I don’t think that the Buddha could make use of parables unless he also expected his audience to see them as parables. That is, telling a parable as if it were true only reinforces people’s misunderstanding, and, even worse, it’s essentially a lie. What may have happened, though, is that most of these parables ended up being interpreted literally with time. This actually makes sense since people in the past didn’t have scientific evidence to cause any cognitive dissonance, so interpreting suttas literally was always the best strategy: if the sutta was indeed intended to be taken literally, then you would get the correct interpretation, but if it wasn’t, you wouldn’t have science to tell you that you were wrong anyways.
The second possibility also seems to be the case. Comparative studies show that many suttas were added after different oral lineages were created. Since changes happened after the division, we should expect that some occured before as well. However, what we do have great certainty is that late tradition didn’t change doctrinal suttas, so things like the noble eightfold path, dependent origination, rebirth, and kamma are the earliest things in Buddhism. Suttas giving precise descriptions of past lives, though, may or may not be early. Most of the Jatakas, for example, are not.
Also, I think it’s important to point out that many of these changes were probably not done out of bad faith. If they were, why should we even trust modern monks if even the earliest ones weren’t trustworthy? Mistakes do happen from time to time, and many of the suttas are actually not intended to be taken literally to begin with. For example, I remember reading that the late commentary admits that sometimes Mara in the suttas refer to a mind state instead of a real god. Buddhagosa also admits that many additions had been made to the mahaparinibanna sutta, which also shows that people were already aware that the suttas weren’t 100% accurate. Moreover, it’s actually not possible to be a fundamentalist Buddhist these days since the Buddha said in AN 8.51 that the true Dhamma would last 500 years at most. The primary purpose of the texts is to provide understanding of the Buddhist path, but the stories told don’t need to be always true. Sometimes, in order to provide understanding, the sutta needs to be both useful and correct, like in doctrinal passages. In these cases, I agree that it would be worrisome for Buddhism as a whole if they were disproved. Fortunately, most Buddhist doctrine is either scientifically correct or unfalsifiable.
Another thing that I’ve noticed recently is that there are just too many suttas for all of them to come from the Buddha. The whole Sutta Pitaka contains more than 17,000 suttas. The Buddha taught for 45 years (from 35 to 80). If we calculate it, there would be at least a sutta for every single day of the Buddha’s career! Of course, a few come from later disciples and many others are quite short, but the size of the sutta Pitaka is still impressive, so I honestly doubt that most of the suttas actually refer to real interactions or that the phrases are exactly what the Buddha said in the real life. They’re likely to be either reconstructions from hearsay or doctrinal teachings expressed in fictional cenarios, instead of accurate historical records. This means that we should expect some mistakes here and there, but we can still expect that the core teachings wouldn’t be changed since they would be present all throughout the canon. Therefore, it doesn’t seem reasonable to reject the whole Dhamma because of a few suttas.