any expert person here please

Sorry, we aren't doctors. If you are worried you should see your own GP who may have received a communication from the Endo setting out his findings.

Not sure if you are type 1.5 or type 2 as your profile says one thing and your footer says another!
This is a guess but perhaps you can educate me here but were the doctors trying to establish if you are still making insulin?
A type 2 would still be making plenty of insulin and hence have a high c peptide level. If you are type 2 then you are insulin resistant and hence require more insulin to overcome this but that resistance has led to your pancreatic beta cells being unable to keep up with demand. The more insulin you take then the more resistant you become.
As you say there are other explanations for c peptide being high but the fact that you have a high glucose levels at the same time suggests that you are making a lot of insulin which correlates with high c peptide.
Please correct ,me if this is far too obvious and I hope a true expert will comment here!

Whether you are type 2 or 1.5 makes a huge difference in what’s happening and why and advice given. Which do the drs say you are? Based on what evidence?

In which case high insulin resistance seems to be your issue.

How do you eat? Is it typical western style high carb or low carb?

You need to speak with your dr or endo to get the information you need. I’m guessing that as a type two producing lots of insulin (hyperinsulimea) they have identified insulin resistance as the issue. And adding yet more insulin will only add to that resistance whilst temporarily lower glucose levels. Perhaps they want to reduce the resistance ie the problem rather than keep throwing more insulin at it and masking the issue. Presumably if there was kidney disease or tumours they’d be doing something about that not just sending you away with lowered insulin.

I’m not an insulin user so please bear that in mind when reading my reply. I’m applying some logic to what I do know. If your readings come down quite well after some hours then that says to me the insulin you do have eventually gets the job done counter acting the carbs you’ve eaten. But not as fast as you’d want.

You say you are low carb and have carb counted (how long have you been on insulin btw and what regime as asked above) I’m wondering if by many type 2 standards it’s still fairly high. Do you know how many? Or can you give us an idea of typical meals? Carbs with insulin are different to carbs without in terms of what’s reasonable or necessary to reduce insulin resistance.

As well as diet resistance exercise, walking and intermittent fasting can help.

Hi. I'm interested in your c-peptide figure. Were you told what the 'normal' test range was. My test showed a figure of 1.19 with a range of 1.1 to 4.4 i.e. quite low. There is no c-peptide test standard range so worth checking what your test range was and where 2.2 fits within it?