I have understood that saturated fats are bigger culprit for type 2 diabetes than high carb intake. Also sugars are larger risk than carbs in general.
The resistance (type 2) is built up over time (historically it was “adult onset”) to insulin spikes. I don’t believe saturated fats introduce sugar into the blood, so they don’t cause insulin spikes, which means they don’t contribute to resistance (at least not directly).
In a roundabout way they may contribute to a surplus of calories and the storage of fat, ultimately causing obesity, which does seem to speed up the resistance to insulin. But all things being equal the same surplus of calories on a high carb diet will be more detrimental because there will be insulin spikes and the insulin will also enlarge fat cells allowing the body to store more fat (ie become obese more efficiently).
So yes eating fats is an issue while eating carbs and spiking insulin. You won’t find a single medical case of T2D where the subject hasn’t repeatedly spiked insulin with carbs/sugar.