I read up on it yesterday after reading your question, and I completely forgot to answer you. It seems IBM is also working with the superconducting electrical circuit type qubits. They say that what makes their quantum processor work with so many qubits is simply many small improvements leading to big steps. Two things in particular stand out to me.

To do quantum computations, you need to interact with the quantum system. However, the easier it is for you to manipulate your qubit, the easier it is for anything else too. For these very small, high-speed, superconducting circuits, vibrations are especially deleterious to performance. IBM apparently delevoped a new alloy for their wiring that comes closest to being in contact with the circuits, for a suitable definition of "in contact". This alloy is optimized for passing current but not vibrations at 4 degrees Kelvin. This is the first improvement they highlight.

The other is a question of architecture. Usually, the circuits and the wires leading to them are on the same silicon wafer, in the same plane and on the same plate, if you like. However, IBM managed to split their circuit up in a way so that all the superconducting qubit parts are on a super cold, low-vibration plate of their own while the wiring to each qubit comes from above or below their silicon wafer instead of on it.

So they seem to be doing lots of stuff! Mind you, I did not read verification of their claims, but I think they sound reasonable enough, though the advances they make probably require a lot of other optimizations behind the curtains as well.

Quantum computing is currently done theoretically and experimentally on multiple kinds of hardware. Each kind of quantum computer hardware setup is called a platform for quantum computing. Each have their own strengths and weaknesses, however, the currently most popular seems to be superconducting circuits. These are what Google are posting most of their money into.

Like the electrical circuits in the computers of your life, these are made by etching or cutting the circuitry onto silica. However, unlike the computers of your regular life, these circuits need to be super cold and shielded from our noisy environment. To do this, they are cooled down to close to absolute zero and kept in a very high vacuum. This is why, if you google images of a quantum computer, you'll see lots of big, cold metal cylinders.

Other platforms of active research include trapped atoms and ions. These would look like a large metallic vacuum chamber with windows, where lasers go in. These lasers are what's used to read, write and cause computation to happen on the ions or atoms. With these kinds of computers, you'll usually see large tables full of mirrors around it for all the manipulations that need to be done to the lasers for them to cause the right computations to happen. These lasers might also be what's holding the atoms/ions, depending in implementation.

Some people are also looking at doing quantum computations in photons. This is way more niche and not as popular, because while quantum computers in general are very difficult to make and operate, currently, these would be even harder. These would probably look like a laser table setup with lots mirrors where the light could be trapped for long enough to do computations.

Some people also believe in interfacing these different quantum computing platforms to make use of their different strengths in different scenarios. This would be far into a future where more than one kind of quantum computer actually works well enough for us to want to interface another good quantum computer with it.

So basically, they usually look large, unwieldy and pretty much like a physics laboratory. Because all quantum computers are, essentially, still physics research labs.