I think you've maybe answeted your own question
@Millie Brown !
All fast acting insulins have a shape over time: for example novorapid typically takes about 20 mins to start working, an hour to three hours to peak and three to five hours to tail off.
View attachment 28524
So, the trick is to figure out how best to match that pattern to your own personal carb absorption rate, which will also be influenced by the GI of the food and what it's eaten with.
In your case, as you take a while to absorb, it's suggesting injecting after the meal is the way to go.
It might be worth asking the docs if there is anything to suggest gastroparesis might be involved. In some diabetics, a complication involves damage to a nerve which controls the emptying of the stomach into the intestine, where the glucose is absorbed. I'm not saying that's what is going on here, but maybe worth asking about if only to rule it out as a possibility.