Is it the high fibre in Huel that causes you issues? If so, id recommend making sure you are drinking plenty extra water, and bring Huel into your diet very slowly.
Start with just one or two scoops a day, and stick with that for at least a week, then build up very slowly. You should be able to tolerate 1/2 scoops a day ok. You can build up to your desired amount over a number of weeks.
Or you may find you can tolerate only one Huel meal per day… (I don’t know what your stomach issue is, but if you feel ok to share, you may find a fellow hueller with a similar condition who may be able to offer some advice from their own experience).
I hope you find a way to make it work for you