There may come to be so many fluctuations in the earth’s orbit, that we would one day plunge too deep into the Sun’s gravitational well, and the end arrives anyway.
I go more along with sunspots, than with orbital variations large enough to measurably affect the earth’s climate. Inertia and Newton’s First Law would seem to apply - an object at rest remains at rest, and an object once set into motion continues in motion, until acted upon by an outside force. A stable orbit, once achieved, remains stable.
If in some four billion years, the earth has not fallen into the Sun, it ain’t gonna happen.
We should be concerned about Andromeda. It will collide with us in that timeframe going forward.
Not perfectly so. The gravitational influence of the nearer planets has an effect on the eccentricity of Earth's orbit.