https://ifconfig.me/. Can also be be curl
'd.
Easier to remember is to just search for what is my ip
in clear net DuckDuckGo (or Kagi if you have it).
they all ask for CAPTYA which is an obvious attempt to obtain ones true IP.
How exactly is a CAPTCHA supposed to discover your "true IP"?
Also note that your IP address is by far not the only thing used to fingerprint you. See https://abrahamjuliot.github.io/creepjs/ and https://browserleaks.com/.
Use TOR browser if you want your starting conditions to be reasonably anonymous.
Even more critical for fingerprinting is user behaviour though.