Ironing between the suns of a good day

This is not a troll and I would be happy if the rabbi would elaborate.

What I thought was that there is a problem with the steam and heating the iron itself (metal embers). In addition, there is a problem with the rabbinic iron itself. And finally, there is a problem with electricity.

On a Yom Tov, there is no problem with steam and cooking metal embers. And between the suns, there is no problem with electricity. Therefore, the question that remains is whether there is a problem with the iron itself.

What I wrote that ironing is rabbinical is only according to what I understood, but could this be a prohibition of a rectangle (a work from the Torah)?

So there is probably an unintentional troll here. What is the point of the sun here? From the law of return between the sun? This is a strange way to ask a question, if you only intend to ask whether there is a work from the Torah or not.
Heating the iron itself may be forbidden from the Torah (although this should be discussed). The ironing itself is not white (although in the language of the Gemara in Hal’ Chav”m and Ablot there is a conceptual confusion between our ironing/washing and their washing/ironing). Why would our ironing be white? What are you whitening there? You are just straightening the fabric. Only if the ironing takes part in the cleaning itself should all this be discussed. You assume that heating in the Yom Kippur is permitted even if it is unnecessary (oh, no) and even that is not simple.

There is no trolling here.
If the iron is heated before sunset, then apparently it is possible to continue and even turn it off before the stars come out (since there is no prohibition on returning between sunsets)?

Well anyway, thanks for the answer.

And another question:
If the soup ladle is in the dishwasher on Yom Tov, is it permissible to open it, take it out, and close the dishwasher so that it finishes the program?
(Assuming you don't change anything electrically)

If you are looking for trolls, then I have now found in the response of Minchat Yitzchak (Zech. 33) a long discussion on whether it is permissible to prepare legumes on the Sabbath.
What is the answer? Of course it is forbidden.
1. It would seem to be forbidden because there is no “because”. Finally, he rejects this view, since it is common among us Sephardim.
2. He did not deprive the fasting person of the dream that he is forbidden to cook for others. And whoever cannot eat it today cannot cook it.
3. Lest he come to eat it on the Sabbath.

As for the ladle, why not?

Thank you very much.
Ironing with cornstarch is considered a form of ironing, right?

I don't know what it is. If it's bleaching (meaning a process that cleans and not just straightens), then it probably is.

A process that whitens and shines linens.

When I think about it, if the iron is hot before sunset and there is no water in it, there is no reason to iron even between the suns on Shabbat Eve and then turn it off before the stars come out.

As I wrote above, in my opinion you are conducting the discussion in an incorrect methodological manner. If you want to clarify the question of what is a rabbinical prohibition and what is from the Torah, it is better to clarify it directly and not through questions about the school, which is vague and depends on other components.
In particular, you are making all kinds of inaccurate assumptions here regarding Shvut in the school. Most methods do not allow for all Shvut and there are many disagreements about this. In the meantime, see a little here:
https://www.yeshiva.org.il/ask/80861

That was the case.

If it is possible to expand on the matter, from what was permitted for a need to what was permitted for an unnecessary need, in order to understand whether heating the iron itself is actually permitted by the Torah on a Yom Tov or not, I would like to thank the rabbi (the rabbi left the point somewhat unclear).

Thank you very much for the reference regarding Shvut. It gave me food for thought (some of which I understood intuitively and some less so).

On ‘from’, see here:
http://etzion.org.il/he/%D7%96-%D7%9E%D7%AA%D7%95%D7%9A-%D7%A9%D7%94%D7%95%D7%AA%D7%A8%D7%94-%D7%9C%D7%A6%D7%95%D7%A8%D7%9A-%D7%94%D7%95%D7%AA%D7%A8%D7%94-%D7%A0%D7%9E%D7%99-%D7%A9%D7%9C%D7%90-%D7%9C%D7%A6%D7%95%D7%A8%D7%9A

Thank you very much.

I apologize for the accusations, but I really thought this was trolling. It was not presented as a practical halakhic question, but rather as a principled discussion.