I've been around the boards for 5 or 6 years and recall seeing you so am guessing you are not new to diet and fitness. Keto isn't for everyone. It is not how I lost my excess weight. My mode was just low carb with a calorie deficit. That said, I seem to be one of the few for whom a high fat diet is effective and when I started my 52 week medically therapeutic keto trial for reason other than weight management ( I had already been at maintenance of a year) I was almost instantly sated from eating so much fat. 75% of my calories in fat. I actually decreased my protein substantially during that trial so was both very low carb and very low protein which is why I feel/know it is the fat that I find satiating.

With the physical fullness, an AWARENESS of my previous HABITS came to light-peering into the refrigerator for something to eat even though I wasn't physically hungry. I recall thinking " if not this (what ever was in the fridge that fit my meager carb and protein macros) then not hunger.

My keto "miracles" had/have nothing to do with "healing" anything except hunger and lousy habits of eating for the sheer joy/comfort/whatever...of eating. I ate for entertainment basically and what was entertaining for me to eat was carby/fatty/salty combos.

I know you are vegan but the concept you mention of eating 2-3 times your previous VOLUME does not compute with me. During weight loss, I leaned towards volume eating with huge piles of low cal vegetables on my plate. My switch to high fat keto caused me to start eating meals out of a little bowl because the volume was so pitifully small. Even at 2300 calories they wouldn't have been what I call "giant". Eating visually tiny meals was a mental/psychological adjustment. I could no longer be visually sated by the mound of food on my plate because it didn't exist. I oftened served up my food thinking, Oh man...is this all there is?

How much dietary fat is "lots of fat"? Others are sated with protein. It's just not my thing. I'll guess you are into weighing measuring your intake?

You say you’re getting enough sodium. How much is that exactly? I hear people say that all the time but then it turns out they’re nowhere near what they actually need for low carb.
You’re probably not going to like or agree with the rest of my thoughts and I don’t know how low carb you are but the lower your carbs, the more protein you need. Plant protein isn’t very bioavailable so you’d need to eat whole lot. Like a lot a lot! If you’re entering ketosis at all your body has to begin making its own glucose since diet isn’t providing enough. Protein is required to do this. If you aren’t providing enough for both lean tissue and bone maintenance and everything else your body needs it for PLUS enough to become glucose then you’re probably hungry due to low protein. Again, not necessarily low as it would be measured on a macro tracking app but you have to keep in mind the bioavailability of plant protein. You have to meet the need that is actually able to be used.
The Protein Leverage Hypothesis would explain how hunger is driven by protein need.
If you are committed to remaining vegan, you could just make sure to always eat enoug carbs to provide all the glucose you would need and never dip to keto levels.
How much that is exactly varies from person to person but I would say not to drop below 150g a day as a general beginning guideline.

One other point to consider is that if you are exercising, you will get hungrier. Try not exercising for a week or two to ease into the keto adjustment to see if that helps reduce the hunger pangs.

3 days is not enough time. Give it time, the cravings will absolutely go away. You might feel them more when hormones change like with pms. Just eat more nuts, more fat, more salt, more water.