Foreign milk

By the way, these poskim also made it easier for actual milk, not just powdered milk. Whoever makes a distinction between milk and powdered milk, in my opinion, is trying to solve the problem you raised, that even if the original concern is not there, a minyan is still needed to permit it. If a difference is found from the original ruling, there is room for permitting it even without a minyan.

It is not certain that this is a decree, there are Rishonim and Achtarim who believe that it is just a concern. Furthermore, there are Rishonim that if the reason is nullified, the regulation/decision is nullified. The poskim you mentioned did not permit it because of this, but because in our reality it falls under the boundary of mir'at which is already permitted in the Gemara.
In short, 3 sides to permit, with the prohibition of the rabbis…

If it is a concern, then it is even easier. See column 2.
The mirta is like not mer'i anafshiyhu (which is said about courts). There is no such thing.
Regarding the nullity of reason, I do not know of any rishonim who believe that a nullity of reason invalidates a regulation. This is against explicit rulings. Even the Rabbis (and other rishonim) who disagree with the Maimonides in nullifying the reason, this is only with regard to the requirement that it be great in wisdom and minyan, but I do not think that another minyan would permit something that is prohibited in minyan.

Regarding concern - clearly, that's what I meant.
Regarding the nullification of the reason, the nullification of the regulation, see Rosh Clal in 2 Si’ 8, Gabi wearing a linen turban. Regarding Gamro. Explicitly, I assume you mean your return to your tents in a sari, the Rosh of course deals with this, Ayish. The Rosh repeats this method (in a less explicit way) in his rulings on E”7 P”D H”7. And a more recent method is in the glosses of Asherah in the inscriptions P”A H”B.
Another anecdote, the Maga in 2 Si’ 9 Sa 5 wants to say that the Shu'a as the Rosh

R’ Yosef Mashash, in his response to Maim Chaim 11, writes an interesting distinction:
If the local reason is null and void, then the regulation is not null and void.
But if the reason no longer exists and is not possible for it to exist in the foreseeable future, then it is null and void. (He writes this regarding the return of the Sh’tz, that today there are no longer people who do not know how to pray but do know how to intend to go out with the blessings of the Sh’tz and understand what it says).

He relies on the Sh’za who nullified kiddush in the synagogue because it is no longer common for guests to eat and sleep there.

As for the Rosh, these are his well-known words regarding a situation in which the reason for the decree is known. I brought them up in the third book when I discussed the annulment of regulations. But he also agrees with the rule that something that is in one minyan requires another minyan to permit. And as for his return to your tents, he himself writes that even there the reason for the decree/regulation is clear, and yet it is not annulled without explicit annulment.
I wrote there several mechanisms for annulment of regulations, and among other things I also brought up the Rosh regarding a situation in which the reason is known (and I compared it to the Rosh in the 19th century regarding the requirement of a taema dekra when the reason is clear) and a situation in which the reason does not belong at all (I think they preceded Rav Mashash in this. See the last chapter of Rav Gotal's The Changing of Natures).

Ultimately, no one disagrees with this rule.

Do you agree that the Chief Rabbi believes that even something that is derived from the minyan (meaning not just “a concern”) is permitted if the reason is clear and does not apply today, since it is said that in the case before us they would not have made a ruling? Like with wine mixed with wine, since the clear reason is that it should be mixed with wine, today when Gentiles do not make a ruling, we say that it was made only for those who mix it. The same applies to milk of Acre. Even if we say that it was derived as something within the minyan (something that, as mentioned, has a concern) because the reason is clear, we say that it was made only for those who mix it. In other words, you are right that it is permissible to annul “something within the minyan” even when the reason is known, but if the reason is known we say that in such a case they did not make a ruling and in any case it is permitted even if the ruling is not invalid by definition, de facto it is invalid.

If you agree with what I wrote in the beginning, it turns out that there are 3 sides to permitting milk aqum:
1. It is only a concern and not a decree, and today there is no concern.
2. According to the beginning - even if it is a decree (i.e. a "matter of right") when the reason is clear and not relevant, we conclude that they did not decree in the case before us and therefore it is permissible.
3. Even if we say that the decree exists and was decreed even where there is no concern, it is reasonable to say that the reality before us is considered a "mirat".

3 Sides of the Permit in the Rabbinic Prohibition

I completely agree.

I will note that in my opinion this is a decree as can be seen from the mishna itself (7:33). There, several laws that were prohibited are cited and at the end it is written that the Rabbi and his court permitted oil - from this we see that these are decrees that require permission and not just a recommendation due to some concern. It does not seem reasonable to me that in the same breath they would bring both recommendations (concerns) and decrees that would require a minyan to permit them.

Shalom Rabbi
Who is careful about milk
What is the ruling on dark chocolate that does not contain milk
But may contain milk … Regarding allergies
Of course there is kosher ou.d
Thanks in advance

I didn't understand the connection to the allergy and the kosher issue. This concern shouldn't bother me because it's likely that there is a cancellation. There is a small doubt here of a nullified minority.