I have. More than I can count.
But the moment Tendou makes the remark about "Natives that mimicked my parents gave me the belt", all that got thrown out the window. It lost all meaning.
No, you haven't commented this last point... in fact, you just ignored it again.
Here it goes... again... In the episode right before the last one, it's shown that Tendo's memories of the day of the meteor fall
aren't reliable. So, his whole story about receiving the belt from his native parents as they die is thrown into question.
In that episode, when he is under rocks after being defeated by Kagami, the flashback plays out again, only he's shown attempting to rescue Hiyori and reach her hand
without the belt scene that he described to Kagami, but failing to do so until a light covers everything and the image disappears.
First we're given that Tendou (who is in fact wearing the belt) tries to attack them but stops after seeing Hiyori beg him not to, then we're supposed to swallow that he accepts a gift from his parents' killers.
Even ignoring the fact that the flashback was shown to be wrong afterwards, he obviously didn't kill them and accepted the belt due to Hiyori. He was completely devoted to her and anything bad happening to her easily broke his cool in the present. I don't see how it's hard to believe he wouldn't kill some people if she asked him to do that, especially considering how it seemed like they were going to die.
Anyway, the parents still weren't a contradiction. Even if you think it's bad writing, there's nothing related to his parents (besides receiving the belt from them) that creates any problems. You basically listed the same scene twice with different names.
EVEN the stuff regarding the belt just hurts foreshadowing. Yes, sure, if GSL were canon, Hiyori's drawings would be much more meaningful and Tendo wouldn't just be spewing empty words when he said that the belt came from the sun, but there's nothing stopping her from drawing some imaginary figure even without GSL nor anything stopping Tendo from considering the belt his own after having it for so many years, even if he received from someone else, so it's not a contradiction.
It IS bad handling of foreshadowing, but it doesn't create a true plothole (unlike the Delta belt in Faiz, which gave special abilities to its human users, but that element completely disappeared when they recovered it later in the series without any explanation).