Ideas to replace meat (lamb or beef) in clear soup. [Warning original Recipe has meat]

dear vegan internet, I‘m looking to boost the flavour in a traditional Arabic dish that is a clear Soup of Onion, Chickpeas, Potatoes and well meat. It is traditionally only seasoned with salt and black pepper. So there are no powerful flavours that could hide the meat.

in the past I simple left out the meat. this was good but not great. I tried to just ad soy-sauce but this coloured the broth dark which isn’t intended. Also it is a Soup that is only simmered or boiled so no roasty notes are intended. any ideas to get clear/ white Umami into the soup?

TLDR: Looking for a Source of umami that keeps the soup clear or bright at least without roasty flavours.