React native (Expo) project shows "cant find variable : require" - react-native

I am an intermediate react developer.
I was running my react native app peacefully without any problems untill one morning, i did not change anything in my codebase but when i tried to run the app through expo client, it started showing the error in the screenshot.
I have checked and checked this platform, and not a single solution.
I am currently using expo sdk 43 (managed workflow) please help...this is my first time posting here.
This is the error below;
Can't find variable: require
http://127.0.0.1:19000/node_modules/expo/AppEntry.bundle?platform=android&dev=true&hot=false&minify=false:5:24.globalcode#http://127.0.0.1:19000/node_modules /expo/AppEntry.bundle?platform=android&dev=true& hot=false&minify=false:720:3.
Click here for the screenshot of the error

I got it fixed.
See what i did,
I created a fresh expo project using "expo init"
Then copied all my files into the new project "except node_modules and .expo folders".
Then i ran "npm install"
Viola!!! Everything works fine now
Note: i tried removing "node_modules" before over and over again and it dint work.
The only thing that worked was starting a new project and following the above steps.

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Now, when I try to do the same thing, Expo Go asks whether I want to open the project in Expo Go or as a "Development Build". It works fine in Expo Go, but crashes immediately when I attempt to open the dev build. The error reads:
null is not an object (evaluating '_ReanimatedModule.default.createNode')
This error is suspiciously similar to one that I encountered earlier in development, which I resolved by downgrading to React Native version 0.69.6. I'm also encountering a second error that says "'main' has not been registered", but I suspect this is downstream of the first error.
I have the same issue when I try to run the app with npx expo start --dev-client.
Any ideas why I might be having this problem?
It sounds like you may have run expo prebuild (https://docs.expo.dev/workflow/prebuild/) which removes "main": "node_modules/expo/AppEntry.js", from app.json. Try to create a new expo app and look at it's app.json file.
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