I incorporate apple into my low-carb diet. I have a gallstone - and I lower the rate of my gallstone attacks hugely by eating apple, so it is well worth it for me. (Note I don't say eat AN apple!)
I like fruit, and I want to eat it - especially the lower-carb variety, so this is the one area in the otherwise healthy food area ('otherwise' as in if one wasn't T2 diabetic and carbohydrate intolerant!) where I well and truly portion-control. To be both low carb (under 50g a day) and have fruit - I eat teeny tiny amounts compared to life before diabetes. (I'm in high summer right now, and really feeling it! When mixing with non-diabetics around dining tables with a well-stocked fruit bowl. Sigh.)
As for apple - during colder weather in particular, I eat a half baked apple a day (8g of carbs). With lashings of whipped cream and greek yoghurt as part of a LCHF diet. I pre-prepare them - taking out the flesh of about six apples, mixing it with A LOT of ceylon cinnamon (the variety of cinnamon that has anti-diabetic properties), pop it back in to the half apple 'boats', bake them for an hour, eat one of the 'boats', and freeze the rest for later consumption. For me personally - whether I eat a half an apple cooked, or not, I have the same kind of BG rise - as in - not too much! (But what is 'too much' does differ between diabetics for sure.)
And one thing that I have noticed in myself is that if my BG does rise, sometimes quite high after fruit consumption (ie - to 8.0 for instance) (although a half an apple with cinnamon and healthy fats in no way does that to me) (but a half a banana will!) my BG lowers to a very healthy level in the post-meal reading. This is where folks are very different. You just have to 'eat and meter' and find out your own fruit-consumption levels? Especially regarding amounts of, and for which fruit.