The physical size of your model does not matter (well, as long as it is smaller than some dozens of km... AC has problems modeling entire cities because of distances from the origin)...
...what matters is how many polygons are in the model. If your 140,000 m2 model is an extremely ornate baroque building with lots or ornamentation that must be modeled in 3D, then it will have problems. If it is a shopping center or office complex, then probably not an issue.
There are people here who have modeled really large projects who I hope will jump in with their experience.
ArchiCAD cannot use dual graphics cards unless there is something new in AC 18 for that.
ArchiCAD cannot use any kind of farm per se... that is, a farm of computers that you, yourself, utilize as you work on a model. It can, however, use a global distributed network of other users working on the same model at once (TeamWork) to get many people working on the same model at the same time in order to get a project completed faster.
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB