There is a version of flannel that belongs in a cabin in 1994 and a version that belongs in your regular wardrobe rotation right now. The difference is cut and weight. Too boxy and it reads like you borrowed it. Too stiff and it never softens into the shirt it should be. The flannel shirts we want are the ones that feel broken in from the first wear, move properly when you reach for something, and look like a considered choice rather than a default one.
We have been paying attention to brushed cotton weights that are warm enough to wear as a light layer but not so heavy they bulk up under a jacket. Collar roll matters here too. A clean roll over a crew neck or sitting open over a tee is where these shirts do their best work. We looked for fits that taper without constraining. These are the flannel shirts that earn a permanent spot in the rotation, not just a seasonal cameo.