Is docker image still fine?

I put it behind a reverse proxy (Cloudflare Zero Tunnel) mapped directly to the 6412 port at localhost (most apps work fine this way).

However, all assets show as 404s:
- /assets/images/logo.png
- /assets/index-Byr2zVf_.js
- /assets/index-Cz4FMEBo.css

I chmod 777 and chown'ed the ./data folder. Anything else I'm not seeing?