Unfortunately I can't see the spreadsheets from those years...but it looks as you were feeding (previously I presume) Royal Canin Dry...this one?
Royal Canin - 'prescription' Glycobalance Protein:51 Fat: 34 Carbs: 14 Phos: 200 ‘prescription’ diet - is that correct?
That would be considered a medium carb diet...so while not optimal for diabetic cats, I suppose it's not as bad as some higher carb dry foods. The contents of that product are however very questionable.
Chicken Meal, Corn Gluten Meal, Soy Protein Isolate, Ground Corn, Barley, Chicken Fat, Natural Flavors, Brown Rice, Powdered Cellulose, Dried Beet Pulp (Sugar Removed), Psyllium Seed Husk, Potassium Chloride, Anchovy Oil (Source of EPA/DHA), Soya Oil, Fructo-Oligosaccharides, Calcium Carbonate, Potassium Citrate,
I see corn, soy, more corn, barley, brown rice...no meat or meat byproducts...lots of other stuff that cats really don't need at all...if meat isn't listed in the first three ingredients it's really not the best choice for diabetic cats...
So, that was then, this is now. I see these foods listed until April:
Humulin & Purina DM wetMay 2020 : Renal wet Current Diet: Hill's k/d (2 pouches) & Sheba Classics pate (1/2-1 tray) per day - free feeding
What are the carb counts on those foods? What is Yanna eating now?
Also, Lantus is a depot drug and it takes time and patience to first; find the right dose and second; build the depot.
I don't see your dosing protocol on your SS or your signature. Am I overlooking it? It will make a difference on how often you increase.
If you're following TR it's time for an increase - if so, please add that to the top of your SS. And then let's review the diet and find out what's on the menu today.