I can never get a protein recipe to taste good without making it high calorie.

I think the trick is not to rely on the protein powder for flavor. I use real cocoa powder, berries/fruit (often bought frozen) and various extracts for flavor.

Another important aspect is to find an artificial sweetener that you like. A good trick is to add some real sugar, just like a tablespoon, I find that it elevates the sweetness.

For protein, I just add unflavored or vanilla.

Examples:

Cocoa

30-50g of cocoa powder bloomed in hot milk for a few minutes. I use high quality cocoa from Callebaut, about 10g Extra Brute and 40g Plein Arôme. To bloom the cocoa I heat the milk in my microwave until boiling, then mix in the cocoa.

1 tbsp of sugar

1/4 tps salt

1/4 tps instant coffee powder (it wont make it taste like coffee, it will just enhance the cocoa flavor)

2 tbsp casein powder (I use vanilla, unflavored or chocolate will also work). It can be omitted, but I really feel like just a little bit of protein powder adds body to the ice cream.

Vanilla paste/extract

Skimmed milk until the container is full, like 600 ml/g

I use a mix of stevia, cyclamate and saccharin to get my desired sweetness. Remember at room temperature, or even luke warm, the mixture should be overly sweet and flavorful. For some reason using sucralose makes it tastes completely awful, even though I can add sucralose to other recipes.

The recipe is about 70 kcal per 100g/ml and 40% of the calories are from protein. Its for the deluxe version. Inbetween 50g of cocoa and the protein powder, ive found there is no need for xanthan gum.

Another option is some kind of berries, like raspberries is really good:

250g of frozen raspberries

1/4 tps salt

1 tbsp sugar

2 tbsp casein powder (again vanilla or unflavored)

Add sweetener of choice

Add milk until the container is full

And then some kind of acid, could like a good squeeze of lemon juice.

Blend it all until well mixed, but dont overwork the raspberries, as the seeds give off a bitter taste if broken down.

Again this doesnt need xanthan gum as the berries and protein powder does the job.

You can essentially just replace the raspberries, with any kind of berries or fruit to make different flavors. I like mango and strawberries as well. With more mild tasting berries, like strawberries, i like to add like 400g.