Selfhosting searxng and can't get Opensearch to work

I've seen that searxng has been recommended here, and after trying it out I was so impressed that I spun up a docker container on my Unraid box. Opensearch works fine with public instances, but I can't get it to work with my container. I'm using the official docker image. Is there something I should watch out for?

I set the instance name, and passed environment variables with SEARXNG_URL and SEARXNG_BIND_ADDRESS.