brotli_static and proxy_pass

[onemantooo]

Hi. We have brotli installed on our nginx reverse proxy, and on the fly compression works fine, but:
We decided to precompress files in our app(some of them hosted also with nginx - but all without brotli).
So when we set brotli off and brotli_static on - brotli compression won't work at all. I think it's because brotli_static designed to work with files and not proxy and it's probably ok, but is there any way to force our reverse proxy look for precompressed files (script.js.br) and if not found - fallback to gzip?