the block needs to be rendered in world in order for this to work. is it possible to piggyback off of the beacon system already implimented tin order to have a guidance block point to the nearest tracker block, even if that tracker block is 2km or more away?

Maybe as a simpler (but more restricted) answer, keep track of last known coordinates of the targeted tracker block, so if the tracker block is at base, the guidance will still point at that coordinate, despite the block itself no longer existing to be targeted.