Miriam was never replaced but fits the request for a benevolent shepherd
My younger son added a great support: right before the section about Moshe's successor is the section of the Daughters of Tzlophchad! (Num. 27:1-11)
This is such a rich concept! In my years of teaching Tanakhm, I never even considered it, but it makes sense (see Michah 6:4, sefaria.org/Micah%206:4)