If you're already using setTimeout, why not just use it directly?

    function clickLoop() {
        document.querySelector('.main-btn').click(); 
        setTimeout(clickLoop, 50) 
    }

What's all this overengineering and waste creating timeouts?

Why not just use setInterval?

    let interval = setInterval(() => document.querySelector('.main-btn').click(), 50) 

Then

    clearInterval(interval)

to stop

How could you be so wasteful traversing the DOM tree every time to find .main-btn? Shame on you.

That's an infinite loop.

Breakable by `clickLoop = null`.

Or use requestAnimationFrame to run infinitely at ~60fps

    window.requestAnimationFrame(function clickButton() {
        document.querySelector(".main-btn").click()
        window.requestAnimationFrame(clickButton)
    })

This doesn't seem to logarithmically scale when you get the click percent increase upgrade, while the other code does.

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