Locking the sandal on Tisha B’Av

Hello Rabbi. I heard the rabbi talk about this once and I’m not sure there was a conclusion on the subject.
Is there room for an interpretive sermon regarding the prohibition of wearing sandals and saying that the sages did not specifically prohibit leather shoes, but rather prohibited comfortable shoes because of mourning, and simply because their comfortable shoes were made of leather, and today most types of shoes are comfortable, and they may have to wear simple shoes or slippers on Tisha B’Av?
Of course, this is a big question because it’s not just about the shoes, but it’s a fundamental question of whether we follow the simple or the sermon.
Did the rabbi have a conclusion on this, does it remain open, and how should we act in practice on this matter and in general regarding these sermons?
Thank you very much dear Rabbi 3>