I used to do a lot of ice fishing here in Wisconsin. Always wore Sorels. Was gone to warmer climates for almost 30 years. When I got back I was going to buy Sorels. My brother advised against that. "That is obsolete stuff" he claimed. Far far better warm foot ware now for cheaper money. I got some Sorels at the 2nd hand store for a couple of bucks with brand new inserts so I used them for the couple of times ice fishing that I went. If I was younger and was going to do more ice fishing I would google the new much warmer stuff. Also as someone has mentioned ...electric socks... That technology is now very viable. It used to be that you would need a motorcycle battery to have enough power for extended electric socks but now ... not so anymore.
I wish I could be of more help by giving specific names brands etc...this is just what I have found out.