Like @aibd already pointed out, it’s both, see section Downloads in the manual install instructions … Install /e/OS on a Fairphone FP3/3+ - “FP3”
A so-called OTA upgrade to a new Android version (over the air, via the updater) should come to FP3 official somewhen, hopefully, if you just wait, most probably from Android 13 directly to 15 then …