some extreme cold pac boots to try if you wish, first are TOP shelf boots, owned severaal of there brand over the yrs, all were GREAt boots but NOT cheap
https://schnees.com/extreme/

and some more run of the mill brand name but with proven good records and in the game a LONG time

https://www.scheels.com/p/mens-sorel...start=26&sz=24

but I think both of these will be heavy to walk in!
ONE advantage of pac boots with removable liners is, you can BUY extra liners, and carry in a DRY one and swap at stand, something you cannot really do on other types of boots!
assuring you , you are starting off with DRY boots on stand!(there also nice when on drop hunts and no other way to dry things, you can dry one and wear one)

or again, I have also just worn the liners inside boot blankets!
so food for thought!