But you need to see it as a whole: the undead part is just a special ability using the same resource as a universal ability. This way you don't care if there are undead or not. Probably you are even happier that you don't have to use it.
If there are no undead, the cleric plays as if the undead parts are scribbled out.
So scribbling out shouldn't include channel divinity, just the undead option.
Post-tashas, it is even moreso, with the channel divinity aliasing into a spell slot on a short rest.
The problem with the ranger level 1 is that you get two very specific abilities that you might not be able to use at all with no compensation.
"if you cannot": Yep. And
even when you use them, they aren't nearly as dramatic as turn undead is.
The action economy of turn undead is crazy when you can use it. Advantage or a boost to a skill roll could still be worse than the modifier some other sage PC has against your favored foe type.
The terrain boost fails to scale; it usually doesn't matter all that much that you can forage for food or track, when you can create food, teleport over terrain, plane shift, divine where your foe is, and the like.
And while the DM can add in "sorry magic doesn't work here or on that foe", saying "sorry, foraging/tracking doesn't work" is equally possible. In effect, for you to shine, the DM has to force the alternatives (which are as effective or moreso without such a veto) not to work.