For making the co-routine wait for few seconds before executing isCoyote = false, you will need to use new WaitForSeconds.

What this function will do is it waits for that delay and then execute the isCoyote = false.

Try this code:

private IEnumerator ApplyCoyote()
{
    isCoyote = true;
    yield return new WaitForSeconds(coyoteDelay);
    isCoyote = false;
}

For making the coroutine wait for a few seconds before executing isCoyote = false, you will need to use new WaitForSeconds().

What this function does is it waits for that delay and then executes isCoyote = false.

Try this code:

private IEnumerator ApplyCoyote()
{
    isCoyote = true;
    yield return new WaitForSeconds(coyoteDelay);
    isCoyote = false;
}