I'll focus on Perception, but most of this answer works for both Perception and Insight... And most any skill.
You're going to have to work with your DM
If the DM sets up the rules that since your passive is so high that it always succeeds, then you'll need to have a conversation explaining that it's not enjoyable for you. Then work together to create a system that lets you see everything, but still get the thrill of a high roll.
Perception (active and passive) is a just a skill like any other
Perception is just a skill, like Animal Handling and Survival. It just happens to be used more frequently than most.
When a character takes the Observant feat, that means they ignored all other feats in order to focus their character on, well, being observant. They wanted to notice all the little details in the world around them. So it's hard to then say that they also want to experience highs and lows when rolling a die. It's hard to ask for bionic legs and still want to run a fair race.
High skill scores don't mean high Return On Investment
Perception is a skill, and like I answered for this other question, skill checks are simply pass/fail. RAW, they are not on a sliding scale.
In other words, just because the player's passive score automatically passes the skill check, doesn't mean they see more/farther/better. They just see something that other's would not. It is only through convention and example that people think that, "because you rolled so high" is part of the rulings for skill checks.
If someone is concerned that the bonus for a skill is too high, just remember that auto-succeeding does not mean that character becomes Sherlock Holmes. Yes, they notice a trap exists, but they don't suddenly understand its mechanics, how to disarm it, what the "payload" will be, and so forth. That will take investigation.
You can succeed on passive and fail on active
I cannot find the tweet/story from Jeremy Crawford, but he describes passive as an always on skill, whereas active is only when called for. So even if a character is looking for one thing, it doesn't mean they can't see something else; or see that thing out of the corner of their eye. Even if you're actively looking for other cars while driving, your passive senses tell you that there is a pedestrian about to cross the street.
Passive and active skills can give different results
Building off the last two points, a tool I use as a DM is that you can get more details from an active skill than a passive skill.
By this, I mean that if the character senses something passively, they know of its existence. But if they sense it via an active skill check, they can decern more.
As an example; say you lost your keys and are searching the house for them. If you succeed with an active Perception check, you find them on the table where you left them. But if you fail the active check, but still beat the DC with a passive Perception check, then, while tearing apart the couch you threw a cushion that bumped the table and you think you heard the jingle of keys. The active score found them directly, whereas the passive score guided you to their probable location. It is important to note that the DM is not changing the DC, but changing how much information is given.
In a dungeon setting this would be like spotting the trap you're actively watching out for versus passively noticing something odd about the stonework.
In terms of Insight, this would equate to passively knowing someone is acting shifty versus actively spotting a tell that someone is lying. Or knowing someone is holding back information versus spotting that they keep looking at a certain picture on the wall when discussing where something is hidden.
In the end
You chose to create a character with high passive skills. You need to work with the DM and hopefully create a system that rewards you for high rolls without minimizing the abilities of the character.