Great info. On a side note I have used Vapor Barrier socks for years. Although rather than the bread or oven bagged technique I have always gone with a brand name sock. Chounaird was the go to VB sock for me until they went out of print. RAB makes a decent one now. I’ve always used these because they are actually ergonomically shaped. Bread bags are cheap but they are shaped to store bread not keep feet warm. I basically had problems with bread bags because they would slip and slosh around and sometimes even creep down my leg creating discomfort. The RABS are made of pack nylon not plastic. Therefore creating more of a non slip surface. Also again shaped like a sock. But also has an elastic gripping ring at ankle level. Those factors combined create a non slip/ stay in place environment. Also especially on multi day efforts they don’t get all Manley like plastic bags do. Another trick is to use a mild roll on antiperspirant directly applied to your foot-skin and or some baby powder to cut down on the perspiration level. Less moisture equals warmer feet and dryer boot lining.I'm in full agreement with @skiguy. A super-gaiter such as the Mtn. Tools is the way to go. The Wiggly's don't cover your toes. and the Neos are a lot of bulk and weight.
Other things that can help:
Toe warmers: Buy them in bulk, and open the packs ~10-15 minutes before putting them on and your feet in your boots. Since they require air for the chemical reaction and there is limited air in your boots, they aren't as effective as handwarmers in a mitten or pocket, but they will help. Vapor barriers. I use Phil Werner's oven bags hack. Look into heated socks or footbeds.
You might try DryGuy Bootgloves or a cheap Amazon knock-off. They're designed for alpine ski boots, but probably help with hiking boots, too, if the fit works.
Keep the rest of your body warm. Throw on a good, hooded, down jacket, e.g. the Feathered Friends Volant or Helios jacket. Throw on a pair of full-side-zip insulated pants, e.g. the Mountain Hardwear Compressor pant.
Feed the engine: Eat carbs and fats, e.g. GORP. Keep yourself hydrated. Bring a thermos of Vermont-Maple-syrup-sweetened tea (low glycemic index) or hot cocoa.
I was going to suggest Mickey/bunny boots, but holy cow!, the price has skyrocketed.
https://rab.equipment/us/vb-socks?srsltid=AfmBOoqX8C3H1xG7VX1XYksVx8MeQbB3TK79N3Yqgd2m4hCZLKG2KMAP