Is my DC-motor strong enough to move this amount of weight?
I would say you would go by trial and error, since there are factors like how the weight is distributed on the motors, will each motor run independently or will you have a closed control loop?
As @tlfong01 said in the comments, you need to know your torque.
Higher torque = bigger force of the motor but slower speed.
And as @Andy aka said, you also need to know your frictions.
Technically, any motor can lift/drag any weight, if it has enough torque, but it will be really slow