I would only try Huel again when diagnosed with Covid and all my taste-buds are disabled. I tried the stuff years ago and during about a year I tried every shake available in Europe. Huel and Bertrand (does it still exist) where my absolute least favourite at the time and ended up binning both.
Plenny shakes can give me a bit of a bowel problem at times but found that the new versions with the probiotics seem to fix this problem. I think the trick is dosing it right and mixing it thoroughly so that there are no lumps in the shake. I do this by first adding some (crushed) ice cubes in my shaker, then add the powder and only then add milk and/or water. The ice helps shaking things up, prevents lumps sticking on the bottom of the shaker and give the shake a silky smooth texture because it freezes the liquid a bit. After doing this for a few years, I don’t even want it any other way.
I understand not all will own a fridge with ice-maker and crusher so if you don’t, just use ice-cubes instead but think the crushed ice gives more surface area, helping the shake to cool faster.