I'm sure it is possible to come up with a solution to the TOR issues here.

How about setting up an account based authentication only to permit posting. This way you can perhaps also edit the posts or even easily remove them should you wish.

Account recovery would be an issue since almost nobody would use their real email to login. My accounts at free email providers have been hacked/compromised before. So email password recovery would also be an issue.

An alternative would be to issue a key in a .csv file where the key is of a length between 20-40 characters and the login asks you for 3 random characters on 3 positions of the entire key when you try to recover the password should this be needed.

For login you get 5 attempts in 1 minute after which you will be banned for 5 minutes. The second band will be an hour. The third ban will be for a day (using fail2ban perhaps). This to mitigate bot attacks.

Where could we reach an admin to propose this? I could even write a script (either Python or Node.js) that can be used for this task where the PHP back-end could send its requests to and receive data success or not.