I’ve asked many rabbis but i haven’t been able to get a clear definite answer, some are too afraid to comment on it, one Rav even said “i don’t answer such questions, ask a mashpia” and the mashpia doesn’t know what to do in all cases
So two scenarios, either one intentionally missed shacharis until after chatzos, then wants to do teshuva later in the day, what does he say? Does one still say korbonos,. Akeida, hodu, boruch sheamar, yishtabach, birchos kris’s shma, and then mincha as the amidah? Or does one only do Shema without any brochos, then mincha? Why should tachanun and everything else? Is one allowed to do a nedavah to make up for the missed shacharis, even if it’s not a real tashlumin since it was intentional?
Also second case, if someone accidentally or do to forces beyond his control, delayed shacharis until chatzos. Does one just do two minchas? What shut boruch sheamar, yishtabach, birchos kris’s shma, and tachanun? Does one day tachanun twice, between mincha and shacharis tashlumin? Any other considerations? Does it make a difference if one started before and got up to ayzehu mekoman, then can one delay all day until finishing?
Please see the following post where you question was addressed https://dinonline.org/2020/08/26/missed-shacharis-and-davening-after-chatzos/
Gmar chasima tova