The insulin you are using is a long acting insulin.
It is used to manage the drip of glucose from our livers.
For someone with Type 1 diabetes, its purpose is to maintain a constant level in the absence of food.
Therefore, it is not used to lower levels.
I believe it is common for someone with type 2 to take only this long acting insulin and rely on the insulin produced by your body to manage peaks from food.
As a non medical professional, the peaks you are seeing suggest your body is not able to cope with the carbs that you are eating.
Reading comments from others with type 2, they have found reducing the amount of carbs (not just sugar, al carbs including the whole meal ones) means their body does not have to work as hard.
However, if your body struggles with a low level of carbs (or you are unable to adapt your diet in that way), you need to talk to your doctor and maybe introduce short acting insulin with food.