Obviously the resulting obesity from consuming excess calories is a risk factor for CVD in itself, but the body of evidence would suggest that someone consuming >10% E from SFA, even if they’re in caloric equilibrium, will be at greater CVD risk than someone consuming less, all else held equal.
The main mechanism by which SFA is thought to increase CVD risk is by downregulation of LDL receptors, which occurs during the digestion/absorption of SFA, and is not a result of excess SFA hanging around in the body in some way. If you consume SFA, this pathway will be in play, regardless of how much is burned vs stored.
There’s no good evidence that seed oils/linoleic acid, refined or not, pose a risk for humans. There’s a lot of talk on the subject about on social media, but it’s almost entirely speculation based on animal studies.
I once bought the anti seed oil line, but on closer investigation of the evidence I changed my view and have replaced most of my SFA intake with MUFA/PUFA, mostly in the form of canola and olive oil.
However, it seems very implausible (or impossible) that humans evolved to need, or benefit from, industrially processed sunflower seeds and olive oil.
How has the total fat in your diet changed? I find it much more plausible that dramatically reducing cheese, cream, whole milk and full fat yoghurt has helped, than that replacing 20mL of cream with 20mL of sunflower oil has helped. It sounds like you have reduced fat overall - why then attribute the benefit to the vegetable oils / fat profile, specifically?
A few years ago, I have been diagnosed with incipient atherosclerosis. This was an unpleasant surprise for me, so I have immediately made serious changes in the food that I eat.
At that time, I was eating very high quantities of dairy, which has a high proportion of saturated fat.
Because I could not see any other factor that could cause the atherosclerosis, I have eliminated dairy from my food and I have changed completely the composition of the fats contained in my food.
I eat only food that I cook myself, so I know exactly which is the composition of the fat contained in it. Nowadays, at least 90% of my daily intake of fat comes from a combination of oils that I use when cooking food (typically 60 mL of extra virgin olive oil + 20 mL of cold-pressed sunflower oil + 10 mL of cod liver oil + 1 drop of an oil containing D3 and K2 vitamins).
Instead of any other kinds of dairy, now I use only a cheese substitute that looks and tastes like melted cheese, but it is made from whey protein concentrate (which has almost no fat) mixed with some vegetable oil and a few other ingredients for better flavor.
After changing completely the fatty acid profile of my fat consumption, after a year the symptoms of atherosclerosis have disappeared and there have been also other very noticeable signs of improved cardiovascular health. For instance, previously, I had cold feet and when sleeping I had to take care to keep them warm. Some months after changing the diet, they had become warm (presumably due to improved blood flow) and I have no longer needed any protection against lower temperatures.
So my diet change has very certainly improved a lot my health in a relatively short time of no more than a year, and that has persisted for the last three years. I cannot know if this is really caused by the change in the fatty acid profile, but I cannot see any other significant difference, except if the abundant dairy that I was eating before contained some other harmful substance or if the significant increase in the amount of eaten EV olive oil and cold-pressed sunflower oil has provided some benefits beyond the better fatty acid profile.
Logically, it is plausible that a reasonable amount of saturated fat, which is correlated with the amount of physical work, should not have any harmful effect.
As long as you burn enough calories daily to use all the fat intake for energy, it should not matter if that fat is saturated fat. However, when the fat is not completely used and some of it is deposited, then it is plausible that it is preferable if oleic acid (mono-unsaturated fatty acid) is the most abundant in food, because in normal conditions this is the most abundant fatty acid in the human reserve fat. When other fatty acids are much more abundant than oleic acid, they must be processed and converted before storage and the capacity for the conversion may be overwhelmed.
The negative connotations for "seed oils" are not applicable to all seed oils, but they refer only to the seed oils where linoleic acid is the most abundant acid.
Linoleic acid is an essential nutrient, but the need for it can be satisfied with 15 to 20 mL per day of a suitable seed oil, like sunflower oil. A greater daily intake than that can cause problems, because the excess linoleic acid must be converted into other fatty acids and also because some of its derivatives have physiological roles for which an excess quantity is not desirable.
Given these, it seems plausible that some fat composition is preferable to others. Like I said, I have acted on this assumption and it has worked very well for me, even if the real mechanism cannot be known, at least not yet.