A question about the Turn server

[Atlantis-Gura]

Hi everyone, I'll say sorry in advance because of my bad English and lack of knowledge about WebRTC.

I've run filedrop on my local server and it's definitely the best in its class! Since the internet provider where I live doesn't provide a public ip, I have to use the cloudflare tunnel for domain access. And then I found that other features work all fine for me, but when both clients are behind a multi-layer NAT, especially if using mobile data, they are completely unable to transfer files to each other.

So I tried deploying a coturn on Oracle Cloud VPS and leaving port 3478 open, then this worked and I was able to relay by setting the turn server address turn:[cloudserverip]:3478 for filedrop.

So with that I have a question, filedrop (WebRTC) is E2E encrypted, but if the file is relayed through an unencrypted (ip+port) TURN server, is it still secure? If I use it this way for a long time, does it pose some risk (In particular the risk of Coturn's Secret being compromised due to unencrypted server ip)? Is it necessary to configure SSL/TLS for the coturn server?

I am indeed confused and I hope you guys can help me. Thank you all in advance.