Fairphone seems to be "introducing" Android 13 in October 2023, and touting a security patch level of August 5:
https://support.fairphone.com/hc/en-us/articles/4405858220945-Fairphone-4-OS-Release-Notes
It's consistently behind in providing updates - if the vendor cannot properly support their device in a timely manner, that's firmware updates that an alternative OS like GrapheneOS cannot ship, the OEM has to ship those. That alone disqualifies a device like that from being considered, aside from the fact that they lack the actual hardware security features which GrapheneOS utilizes and considers necessary.
"Years of support" are no good if it means providing some updates, sometimes, after significant delays. Support should mean timely support. If GrapheneOS said it would support a device for its entire lifetime, but delivered patches months late, would you consider that acceptable? My guess would be that if you're using GrapheneOS, you care about receiving the latest security patches as a minimum, so the answer to that would be no, so why should Fairphone get a pass?
It is unfortunate that people fall for their marketing and think that the device is somehow a good or viable choice, or that it's somehow special and provides something that other devices don't.
Even from a repairability and sustainability perspective, I would argue that a Pixel 8 that will be receiving 7 years of proper and timely updates is a better bet. Google also seems to have committed to providing parts like screens, cameras and batteries for the entirety of the device's lifetime through ifixit. Could it be easier to replace the battery in the Pixels? Absolutely, and I would love to see OEMs move back to that, but again, that doesn't make a phone like the Fairphone a good choice until it can provide the bare minimum.