If Coh gets a nerf, which one would you prefer its effect?

Neither.

Killer smashes totem when snuffing it, and it can be relit with Pentimento, but it's still infinite (as long as dull totems remain).

Alternatively, healing with CoH is infinite but takes twice as long as Self-Care and speed doesn't stack with healing items/perks, or else CoH can only be lit once per survivor running it.

The we'll make it effect is probably one of the largest contributors to the strength of Circle of Healing, reducing that to something like 50% or 20% or even lower, if they're not willing to flat out get rid of it completely, is one of the easiest solutions to bring Circle of Healing more in line.

I agree with @sizzlingmario4 who brings up the idea of a cooldown- either on the perk itself (probably slightly shorter like 60 or 80 seconds) or on the individual totem it was last attached to (probably slightly longer like 90 or 120 seconds) which means you could rebless a different totem immediately. An important note about the cooldown, is it would obviously need to begin immediately after a blessed totem has been snuffed out, not after it's been placed, because if you start the cooldown right away there's a decent chance the killer doesn't snuff the totem out until after the cooldown has already expired meaning that it would be useless. This also means that switching where the blessed totem is should also not have anything to do with cooldowns.

However, I disagree heavily with the idea that boons shouldn't go through multiple floors. What I've realized in many conversations about boons as a whole, is that people really address changes like that to CoH specifically, which isn't good. Circle of Healing is a problem, I agree- but other boons like Shadow Step, or Exponential are actually very much reasonably balanced between the effects the provide, the time investment required to put them up, and the thought / strategy to put them in places where they might actually get use- but hopefully wouldn't get snuffed out immediately by the killer.

Removing Boons ability to go through floors would actually weaken perks like Shadow Step and Exponential considerably, and would only hinder the strength of Circle of Healing slightly, making that change overall a negative one. You'd only mildly impact the use of CoH, but in exchange you would very much discourage the use of the other Boon perks, reducing perk diversity, and potentially inadvertently encouraging the use of CoH because you'd simply have more opportunities to use the perk effectively regardless of the floor restriction or not. Whereas perks like Exponential and Shadow Step depend in a significant way on being able to go through floors.

Instead what I would do is I would apply any restrictions like this to CoH specifically, rather than boons as a whole. I'm not a fan of making wide sweeping boon changes that affect all boons, because not all boons are the same strength. Even with only 3 boons in existence right now, we are seeing instances of Strong, medium, and weak power boons:

• CoH is undoubtedly extremely strong. Not much to it.
• I would argue Shadow Step is actually a decent perk of a medium strength in it's own right, you can really mess up a killer's chase potential by blessing it in the correct place and running into that area and quickly losing Line of Sight- especially when you're uninjured so you're not bleeding or whimpering either. Synergize this with other perks like Quick and Quiet, iron will, lucky break, deception, etc. and you could make a nice "combat stealth" build.
• Exponential is undoubtedly the weakest because it is so circumstantial: it depends not only on the killer to slug you on the ground at all, but also that you go down in the relative vicinity of your boon such that you can recover immediately or are within crawling distance to recover yourself. Not to mention all the time it takes to recover in the first place, so not only does the killer need leave you alone, they must leave you alone for long enough that you have the time to crawl within the vicinity and recover yourself. In the niche circumstance that all the conditions are met, you might see some genuine value come from Exponential however.

So if you've got 3 different perks of very distinctly different strength levels, why is it necessary to apply the same changes to all of them? The truth is Shadow Step and Exponential are already completely overshadowed by how strong CoH is and nerfing them just because Circle of Healing is strong is really just adding insult to injury at that point. You'd end up nerfing two perks into obscurity (and at this point I'm not just talking about the multiple floors thing, I mean applying changes to "boons" as a whole rather than fixing what we know is the individual problem: COH) just for the sake of slightly taming back CoH- which is going to be used anyway because any incarnation of Circle of Healing is going to be strong that's just how it is.

So long story short, just reduce the range of Circle of Healing from 24 meters to something smaller like 16m or even less. I still am not aware if Circle of Healing works in a cylindrical 24m (as in, so long as you are 24m away from the boon horizontally it can be used) or a spherical 24m, which might change how you rework the perk, but either way range reduction is range reduction nonetheless. So long as it is applied Specifically to Circle of Healing, which is the main point I wanted to get across.

A third type of nerf is they can adjust the healing speed bonus on all healing. Hypothetically they can set that number anywhere from 0 - 100%. Depending on how much they end up wanting to nerf it they can use that as the nerf itself or use it in combination with removing one of the other effects to finetune it.

Neither

If killer snuff a boon the totem should break.