It's not the weight of the fuel fighting against gravity that is the problem. It is the inertia of the fuel preventing you from accelerating your rocket up to orbital speed. The main effect of more gravity is to increase the required orbital velocity. You need to go even faster, requiring more fuel, requiring even more fuel to accelerate the fuel and so on.

There will be more loss fighting gravity if the earth were bigger, but it is the increase in required final velocity that makes it impossible to achieve orbit with chemical rockets in this case.

Accelerating stuff at ground level definitely helps - see Spin Launch. Unfortunately, Earth having an atmosphere places a big limit on how fast you can get until you are above most of the air. You could spin launch to orbit (with small rocket corrections) on a huge planet, as long as there was no atmosphere. You could even launch people if you had a long linear accelerator rather than a spinning one.

The problem with getting to orbit is that you need very high velocity to stay there. Altitude and atmosphere resistance are much less relevant than speed.

People often get the idea that if you launch from 15000m up and flying at several hundred km/h, you are a long way towards space and above a lot of the atmosphere. Unfortunately, overcoming altitude and the atmosphere are fairly small fractions of what you need to stay in orbit. You need to accelerate to around 27000 km/h to achieve orbit, so the benefits of a high launch are not as great as you would think. You are generally better off with a bigger rocket launched from the ground.