Why does a shofar have to be davka from a שְׁפוֹפֶרֶת, from a horn whose inside layer can be removed?
The symbolism of וּמַלְתֶּם אֵת עָרְלַת לְבַבְכֶם , removing the layer of "foreskin" on the "heart." A difficult task indeed.
https://thechesedfund.com/rabbikatz/support-rabbi-katzz-podcast