I wear pac boots quite a bit all winter.
For an active pac boots, you don’t want double insulated rubber. Hoffmann double insulated felt liner boots are the warmest, but also not boots you can walk in.
Something like a schnees hunter (wouldn’t buy them again) that is a single piece of rubber on the bottom with a decent thinsulate bootie is what I use for 90% of winter stuff.
Fit on these boots can be controlled with different thickness felt insoles.
They are not great hiking boots, more of a flat, non supportive boot, but I prefer that anyways.
If I was in the market I’d probably try Hoffman first, though I don’t know if they make a single wall rubber bottom without a steel shank. Kenetrek are probably made in the same place as schnee and cheaper.(edit, I guess not anymore)