Is there a vegan substitute for fish sauce?

Hi! I hope this is okay to post here.

I’m personally not vegan, but I’m a worldbuilder, and I’m currently building a fantasy culture that I’ve decided has a ton of vegetarian/vegan dishes, due to meat being expensive. I know, food is far from the most important part of building a fantasy culture, but I find it to be one of the most fun parts.

However, when looking for inspirations for the flavor base of this country, a lot of the ones that resonated with me include fish sauce as a primary source of umami. While I very much think that a salty umami works perfectly for this culture, I realized that it wouldn’t be accessible to people who don’t eat meat. Thus, I came to y’all, the experts.

Are there any vegan alternatives to fish sauce when it comes to providing a salty-umami flavor in cooking?