If you want, you can add a dash of cream, but then of course the dish is no longer vegan. Alternatively, take some soy cream (but incompatible with HI!).
If you suffer from histamine intolerance (HI) you should be careful with pepper, it can be a histamine liberator, I just leave it out. Likewise (if at all) only use broth that is free of yeast, yeast extract and / or glutamate (organic shop, health food store), make sure that there are not incompatible vegetables in it.
Chestnuts usually do not cause any problems. If you are not sure, please test it beforehand. If you use a frozen product, you must make sure that there are no additives (e.g. preservatives), add frozen chestnuts to the soup, do not allow them to defrost beforehand.
The soup can also be refined with curry and other spices, but this is not recommended at HI.
This goes very well with baguette bread fried in a little olive oil and garlic.