2005 Ford F-250 — dPF regenerations seem much more frequent

Write down what you already tried. A second data point from another 2005 Ford F-250 owner helps more than a generic diagnosis. I'd do that before spending real money. Take it or leave it — that's what I'd do. Not trying to scare you — just skip the expensive first guess. Might be overthinking it, but I'd rather overthink than overspend.