A compromise — #16 of 31 Flannel ranks #16 of 31 fabrics for odour resistance. It is a middling fabric for this. Ranked with a wool-family bonus plus breathability and moisture management. The top pick is Merino.
Flannel measures 58/100 for breathability, 12% moisture regain, 80/100 warmth, at 260 gsm. Wool fibres lead here: Flannel is not a wool fibre, so it leans on breathability alone.