MacBook Air M1 keyboard and Trackpad freezing

Basically , my Mac m1 air is good but its keyboard and mouse keep freezing again and again, like some times after 2 minutes or so , sometimes just after restart they both freeze and sometimes they work good for long hours without freezing.

I have tried to solve the issue here is all what I have done

boot in to safe mode -> issue persists

make a new user -> issue persists

backup and reset disk and reinstall Mac OS -> issue persists.

So none of the solution of worked, to debug what is the issue when my keyboard and trackpad froze I connected my external keyboard and mouse to it and I was able to work smoothly by using them even though my MacBook's keyboard and mouse were not working.

I visited Apple Store and technician said there is no issue as their diagnostics said no issue and they will have to send to repair the parts which basically costs a lot.

What I want to understand is like after seeing all this , even a noob like me can say it is not an hardware issue because if it was then why does it work fine for long hours without any issues.

I have missed a lot of deadlines because of this issue. Kindly look into this . I have read various posts and put a lot of effort in this issue.