If I understood you correctly, the last pshat from Rav Ilan ,is a good tzu-shtel to what you wrote. Piska Tuva
We read toward the end of Parashat Vayelekh (31:28) of Moshe’s instruction to the Leviyim to assemble the nation’s leaders so he could present to them the poem of Ha’azinu. Rashi, citing the Midrash Tanchuma, raises the question of why the chatzotzerot (trumpets) were not used for this purpose. As we know from Sefer Bamidbar (10:1-10), Moshe was instructed to make two silver chatzotzerot which the kohanim would blow on certain occasions, including to announce the assembly of the entire nation or its leadership. Seemingly, if Moshe wanted to summon the nation’s elders, he should have had the kohanim sound the chatzotzerot. Rashi explains that the chatzotzerot were not used because they were buried that day. The trumpets were not left for Yehoshua, Moshe’s successor, and they buried on the day of Moshe’s death – even before he died – as an expression of the concept, “ein shilton be-yom ha-mavet” (Kohelet 8:8), meaning, that even the most powerful figures forfeit their authority in the face of death. Thus, when Moshe summoned the elders, his chatzotzerot had already been buried, and Yehoshua was not yet the nation’s leader, and so his chatzotzerotcould not be used.
Rav David Mandelbaum, in his Pardeis Yosef He-chadash, presents three possible reasons for why Moshe’s chatzotzerot were not handed down to his successor. First, Rav Mandelbaum suggests a halakhic reason, noting that Moshe had the formal halakhic status of a king. (The issue of Moshe’s status as king is discussed at length earlier in the Pardeis Yosef He-chadash – Bamidbar, vol. 1, pp. 376-7.) The Gemara in Masekhet Sanhedrin (44a) establishes that after a king’s death, his scepter may not be used, even by his successor. And the Rambam (Hilkhot Melakhim 2:1) rules that all the king’s personal items are destroyed after his death. For this reason, perhaps, Moshe’s trumpets had to be discarded, and were not to be used, even by his successor, Yehoshua.
In a much different vein, Rabbenu Bechayei, in his commentary to Parashat Beha’alotekha (Bamidbar 10:2), writes that the sounds blown by thechatzotzerot were actually expressions of profound wisdom, which only Moshe, through his unparalleled prophetic capabilities, could understand. The chatzotzerot made by Moshe were buried, and not used by anybody else, as an indication that only he was capable of understanding the deep messages conveyed by the sounds of the trumpets.
Finally, Rav Mordechai Ilan, in his Mikdash Mordekhai, views the burial of the chatzotzerot as expressing the notion that each leader uses different “instruments” in proclaiming the immutable messages of the Torah. Moshe’s chatzotzerot were not used because leaders should not necessarily look to mimic the precise methods and strategies used by their predecessors. While the laws and values remain the same from one generation to the next – just as the precise same sounds were blown with every set of trumpets in every generation – the “instruments” used by leaders and educators to communicate those laws and values must be altered and modified to suit the needs of each particular age. Yehoshua was, without doubt, to transmit the same Torah as taught by Moshe; however, he was to use different “chatzotzerot,” different tools and media to convey the Torah. Moshe’s trumpets were therefore buried on the day he died, to teach that each leader must choose the means of communication that best suits him and the particular needs of his generation.