If we somehow fix the Sun's luminosity indefinitely at current levels, stabilize the Moon's orbit so that it no longer drifts away, and match the solar tides precisely with lunar tides so Earth's rotation no longer slows down, what would happen to Earth's landscape eventually? The tectonic activities will eventually cease. What happens billions of years after that? Will the continents eventually sink below the sea and leave only archipelagos?
EDIT: My bad. I should have stated more clearly my intention. I'm primarily interested in geological processes in geological time horizons after tectonic ceases completely, not cosmological or other theoretical physical scenarios. The emphasis is on sufficiently long after tectonics ceases, not what ifs of a future truly eons after that. So, here's my restatement of my problem.
If we hold every other variable constant, e.g. sun's luminosity, Earth and Moon's orbits, magnetic field, replenish the water lost from Callisto, etc, how would the landscape evolve?
Assuming we still have rainfalls and plant growth continuing indefinitely after tectonics ceasing, will rivers eventually become fjords and deserts eventually have all their sands blown off, flooded and eventually become shallow seas? Is it possible that, even with well-forested areas, billions of years of rainfalls eventually leach the whole continent away ion by ion, so that we have nothing but a global ocean in the end?