A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
SWITCH is not the best function for this. Try
=LET(d, N2, t, TODAY(), IFS(d>=t, "Still active", d>EDATE(t, -6), "<6 Months", d>EDATE(t, -12), "6 Months - 1 Year", d>EDATE(t, -24), "1-2 Years", d>EDATE(t, -36), "2-3 Years", d>EDATE(t, -48), "3-4 Years", TRUE, ">= 4 Years"))