Change socks and liners when you get to your stand. Use boot blankets and a piece of foam under your feet. Key is keeping your feet dry and core temp up. I use hand warmers in my gloves and one in each shirt pocket.

Did a number of Alberta deer hunts.
The best I found.
https://www.herooutdoors.com/canadian-military-issue-arctic-mukluks-used/
Canadian Armed Forces Arctic Mukluks
Not that good for walking.
You tighten them up as much as you can for the walk in.Then pop the laces for your sit.
Everyones threshold for how much they can take is different.
We found that these would keep you on stand.
Kinda important when the hunt is expensive and you have limited time.
A light weight sleeping bag up to your arm pits.
Better yet.

dave

Find some bunny boots.

I've been the first guy to get cold feet since I was a kid. As was said above keep the rest of you warm, if core temp drops the blood flow to feet and fingers cuts off first to compensate.

Extra socks, special socks never worked for me. All they did with proper fitting boots was cramp my foot and diminish circulation. Only thing that worked was wearing boots one level of insulation greater than everyone else. Now I have several levels to choose from starting with 200 gram boots for upland to pacs that I use for ice fishing.

What I wear is always a balancing act. Morning sitting gets more insulation. But if I have to walk in a ways I'll pick a pair that I know will keep my feet warm til the planned break if no longer. Then as strategy changes I'll go to a lighter pair of boots. And keep a change of socks handy in case you misestimate and your feet sweat.

A bit of a juggling act and a PITA in general but that's the only thing that works for me.

Maybe I'm doing it wrong but chemical heaters in boots do nothing. They require air (oxygen) to work and rammed in a boot they don't get enough to make a difference.

(Have some bunny boots inherited from my mailman uncle, they were a favorite in the day among mailmen walking routes. They are horrendous compared to boots of modern construction.)

Have some other ideas like insulation under your feet while sitting, and a down vest or chemical heaters covering the kidney area. That's where I feel cold creeping in. But in eastern SD strategy changes as the day wears on and we're never more than a half-mile from a road. So the basic strategy works well.

You can go a lot farther in warm bunny boots than you can with two frozen lumps at the end of your feet. Break thru a layer of ice and fill your boot with water and get back to me on how good your pak boots are. Ed k

The great thing about bunny boots is they keep your feet warm even when wet. No boot with a exposed liner will do that. They are litteraly the only thing that will keep my feet warm when stand hunting in cold temps.

My feet are chronically cold when stand sitting, lack of circulation is the issue when sitting for long periods. I recommend boot blankets but carry to stand and remove hunting boots and wear boot blankets over socks with foot warmer added. Loose fit and air is the key. Also, standing up at least once an hour helps.

Loose fit is crucial, as is some kind of insulation not to place them directly on te frozen ground, and either a down or fur hat and neck gaitor.

Russian foot-wraps, under wool socks, and set your boots on some sort of insulator, even if it's just a pile of stick. However, that can be noisy if you move at all. Best to take a small foam pad for the job, and another one under your butt.

Another solution is not to sit still. n moving slowlyt helps considerably. But apparently that is less and less possible in today's hunting, due to too many humans cluttering up the landscape.