Then you're not looking well enough. What's your passive Perception again?
I've looked off and on for years, on multiple sites and read dozens of articles and watched about 4 or 5 different video essays.
But sure, I just haven't looked hard enough, that must be it. Not that there is a fundamental problem in how traps are interacted with. What was that thing they said... something like if knowing how the trap works and where it is means it isn't a challenge, it wasn't a challenge in the first place, just a gotcha. Don't remember which resource it was that said that, but it fits with my experience.
You don't roll. If it was a situation you couldn't fail, you succeed without a roll.
I know, and yet time and time and time and time and time again, we end up in this situation where despite being unable to fail the roll, we have to make it anyways. Mostly because the DM either didn't think of a DC beforehand, or because they ignore the rules and say that 1's fail, so there is always a "chance" you can fail no matter what... then they forget that the rogue can't even roll a 1 after a certain point in time, so we are just rolling meaningless rolls.
And, it still doesn't anwser the original question, what is the point of putting in a trap that the party is going to automatically bypass without rolling? What have you accomplished?
Uh, yes. You do that so they can use their feature. Do you never use undead below CR 1 in an undead campaign just because the cleric has Turn Undead? You're essentially nullifying that feature and they might as well not have it anymore.
Turn Undead isn't a passive, always on feature. But yes, if any undead lower than CR 1 disintegrated whenever they got within 30 ft of the cleric, then I would probably be very tempted to stop sending undead at the cleric, since they are just wasting time.
The ambush imparts the surprised condition just before combat is rolled. It occurs too late for the cleric to verbally react and discuss with others.
So, the cleric spots and ambush from any distance (because there is no distance limit on sight) and they can't talk to the party because they couldn't see the ambush before the surprise round happened... So there is no point in the Alert feat if you have a high enough passive perception, because the result is the same. All it does is prevent surprise, it doesn't actually allow you to spot the ambush before it happens. Ambush still happens, you just can't justify the cleric being surprised.
I'm pretty sure none of this is in the rules, and it seems that the entire point of it is to just force ambushes to happen anyways, no matter what the passive perception is.
When you perceive something, you'll notice the object but you won't know more until you investigate. The players can make assumptions and avoid everything but that's dangerous in-and-of-itself.
All it takes is for them to say "I want to take a closer look" or "I want to turn away," then they deal with those consequences.
Right, doesn't matter what the passive perception is, they have to then go and roll to be allowed to see the trap. Thus forcing the trap to still be relevant, despite being spotted.
Might as well just remove passive perception from the game.
I believe the crutch of the miscommunication is that your DMs appear to improvise the game on a session-to-session basis. I do not.
I've already completely created the adventure by time the players sit at the table for session 0. The maps, the lore, the dungeons, and the wilderness are done and I run them as written. I improvise the interactions but once a trap is set with a DC and an effect, its there and I'm not changing it. If the players somehow pass it with ease, cool. They should feel proud of themselves.
I'm not one to enjoy curated games because my choices begin to matter less and I'll end up with some bitter mindset about the game.
I can't say I'm surprised by that, you definetly seemed like the type to plan out every aspect of the game and try to deviate as little as possible from your plan.