I suspect the submarineman meant to post NZF (not NFZ), which is one of the muni CEFS I own in my taxable brokerage, with about 5 others. I could be wrong, but at least I feel right!
To the original OP's question, it sounds like muni CEFS (highest risk) or a muni ladder or a term limited muni ETFs (these are less risky) are the way to go. I own muni CEFS in about 1/3 of my brokerage for the tax reasons stated. SBI and VKI are two others. I am intending to sell MMD as a tax harvest loss at some point, when I get off my duff and get motivated--maybe I will "win" and lose more (obscure reference to Ralph Stanley's great "When I Lose" bluegrass song, for the unenlightened, which is most who didn't live in Appalachia or the Ozarks). .
When the Fed raises rates vigorously, almost any bond fund, except floating rate funds and a few others will get smoked. I remember the "good old days" of Tall Paul Volker, when mortgage rates were 16%--but I'm old. As with stocks and stock funds (and inflation risk with CDs), you belly up to the table and take your risk and take it like cod liver oil.