You are likely thinking of some form of geothermal that is based on shallow pipes in the earth rather than geothermal that taps into the hot core of the earth. This is a very significant distinction.
While geothermal powered from the hot core of the earth can be used to power whole cities, it is only rarely possible on the scale of a home. One would need to have hot springs nearby.
Well, those geothermal units people use for heating a house or a community CENTRE can be but rarely are designed to produce surplus power, as in electricity. Usually we are pumping heat out of the ground and pumping heat for storage into the ground. Depending on design, these units can deliver heat with almost no input energy but usually about 1/3 the energy they deliver. It costs more money to have an installation that delivers more than 3 times input energy.
Now solar thermal can be designed to store energy with or without pumping. When pumping is used our energy cost is very similar to slightly less than the cost of energy pumped from shallow geothermal. But when we are capturing winter sun to heat domestic hot water, we would get perhaps a doubling of input energy. You would get better economy with geothermal.
My house is heated with solar thermal, but no pumping. So I have no input energy for that derived energy. Our penalty is that on occasion we have less than comfortable temperatures and no way to extract more heat from the sun. That means we have to use about a cord of wood each winter to remain comfortable.
When we considered geothermal, the efficiency of heat pumping was in its infancy. Had we chosen to go geothermal by now we would have had to replace heat pumps, and all the while we would have been dependent on a supply of electrical power. By contrast we have never had a day that we could not have got along with just a jacket and cap to keep us warm. We have gone on winter vacation without having secondary heating, and no fear of freeze up should power fail.
Our home is an earth embanked slab on grade design that stores its heat in rock and concrete. The sunlight just shines in our large window space and sinks into the thermal mass. This means that sometimes in the coldest part of winter we are ventilating to avoid overheating, That would be 3 to 5 days in a winter.
We do not need air conditioning, but solar thermal does not offer that service with this design.
Even with a geothermal heating system I would suggest designing the house to take advantage of available sun heat. It cuts down the demands on the geothermal but more importantly it provides some heat when you do not have electricity. You might use solar photo voltaic to power your geothermal.