In general, /e/OS is based on LOS, but the project decides which devices it supports.

https://doc.e.foundation/support-topics/support

/e/OS is not dependent on LineageOS in deciding which devices to support or stop supporting. We already have several devices which are not on the LineageOS supported list. We plan to port more devices to work with /e/OS code.

Maybe, to make things work, /e/OS team had direct help from Fairphone, as their OS is also somehow ‘official’, while LOS did not and still struggles.