Most CAPTCHA's today also look at meta signals.

You can significantly increase your success rate by adding some "random human" actions:

- wiggle the mouse a bit, don't go in a straight line

- click multiple times in quick succession on a image

- wait a bit before clicking the Submit button after selecting matching images

- match a wrong image and then immediately unmatch it (as if a mistake)

- click randomly on the page around the CAPTCHA

- resize the window a bit, rotate the scroll mouse a bit

And don't do the exact same thing every time, improvise, pick randomly 2-3 actions from the list.