As stated before you don't need a reverse proxy. Since you are exposing port 8080 ( if you stuck the config on the docker hub page; "-p 8080:80") it is reachable from everywhere, where you have access to that machine.
A reverse proxy can expose many different services running either on the same machine or from a remote. As long as the reverse proxy is in the same docker network (usually "default") it can access your services without their ports exposed.
You can configure the reverse proxy to decide which backend service to call by path, dns name or other patterns.
A reverse proxy can also do TLS termination and get certificates from let's encrypt, so the backend services don't have to deal with it.
So if you run more than one service on the same machine and want to use TLS you normally want to use a reverse proxy.
I personally use traefik because I used to but I also used nginx and caddy. Whatever works for you. But I agree that caddy is easier to get going without a lot of boilerplate config.
I don't recognize any difference on my Pixel 6 Pro.
Bought Sync Pro twice, after problems with the IAP. Would gladly buy again just to get rid of the ads, even for a higher price, but subscriptions are a big turn off.