There’s some good evidence behind warm / hot / cooked food being easier to digest.
Some people have such strong systems they can digestive almost anything.
But it is quite a common thing to struggle with cold breakfast especially very early in the morning - digestion can be sluggish in the first couple hours of waking in the morning. And warm food or drink can ‘light the digestive fire’ so to speak.
Try drinking a cup of warm water prior to your cold Huel, or try out what @Africorn does - Mix the Huel in a small amount of water, then top up with hot / warm water (don’t shake at this point!!! Just stir) It’s actually fairly pleasant to drink warm.
My favourite warm Huel recipes:
Peanut butter in unflavoured
Water infused with Chai teabag plus Original
Hot chocolate Huel (or mocha)
Matcha and Original
Spiced Golden Coconut milk plus UU
Always best to mix Huel into cold water then add hot and stir. Or mix with warm water in a blender