Plex in Docker, with nginx-proxy, let's encrypt for use with Cloud Flare
You need to create a docker network that your containers will communicate on for the reverse proxy.
In these examples, we will use the proxy-tier network.
docker create network proxy-tier
SSL: Full (Strict)
HTTP Strict Transport Security: Disabled (you can enable, but beware, not really necessary).
Opportunistic Encryption: On
TLS 1.3: Enabled+0RTT
Automatic HTTP Rewrites: Off
Rate Limiting: Off
Securty Level: Essentially Off (I turned this off because didn't want users to potentialy be challenged by Cloudflare which would break Plex. You may be able to play with this)
Challenge passage: 30 minutes
Create a new A Record for your Plex Server and point to your IP. You can try testing with the cloud icon "grey" (bypass cloudflare) to ensure your setup it working, then enable it when you're sure.
Caching Level: Standard (you can play with this. Some use No Query String). YMMV
Browser Cache Expiration: 4 Hours
Always Online: Off (you may want to leave this On if you serve other sites from your domain)
Development Mode: *Off
HTTP/2 SPDY: On
IPv6: On (change this depending on your environment)
WebSockets: On
IP GeoLocation: On
Maximum Upload Size: 100MB