For building a quantum computer a distinction is made between logical qubits and physical qubits. The physical qubits correspond 1-to-1 with the underlying phys

For building a quantum computer a distinction is made between logical qubits and physical qubits. The physical qubits correspond 1-to-1 with the underlying physical media i.e. each electron spin makes one physical qubit. The physical qubits have a lot of noise, so can't be used directly to do computation. Instead you do error correction on many (3 to millions or more) physical qubits to make one logical qubit that is noise free. These logical qubits are then used to do the actual computation. Your estimate of q=8192 is for logical qubits. The actual physical qubits will realistically go to millions, unless some really fundamental breakthroughs are made.