Using asymmetric encryption + key rotation, is it possible to make an extra obfuscation layer?

Question

I'm building a service, that works as the cipher and decipher for instant messages. It works by following the following steps:

1. The sender encrypts the text(not long, mostly chatting messages) using a public key;
2. The sender saves the encrypted text to a server. The server generates a customized URL schema as the link that points to this text and reports the link back to the sender. (For example, magnet://, here I use something else as crypmesg://msg123)
3. The sender shares this link in an app;
4. When the receiver gets the link and accesses the link, the receiver downloads the encrypted text. After the server confirms the text has been downloaded, the encrypted message and the link will be erased;
5. The receiver decrypts the message locally using the private key.

However, I noticed that at step 3, if I try to share some content that is under censorship(in this country), they might block the message, or go watching this user more closely since such a user behaves abnormally.

Is there any simple method to make this link not detectable by machine? Like making it into a random string that uses the local language characters.