Recent advances of quantum information processors have opened up new horizons in science and technology. However, many challenges remain on the journey to achieving deployable quantum technology. In this talk, I present Hamiltonian engineering methods to overcome some challenges of fixed-frequency superconducting devices. Many emerging quantum architectures have fixed spectra to achieve high coherence, but as a result, the types of controllable interactions are limited. Endowing these promising platforms with the same interaction toolbox available to frequency-tunable devices will significantly extend their capabilities and performance. To this end, we adiabatically transform fixed-frequency superconducting circuits into modifiable Floquet qubits, and demonstrate an XXZ Heisenberg interaction with fully adjustable anisotropy. Importantly, our Floquet protocol is applicable to various fixed-frequency high-coherence platforms, thereby unlocking a suite of essential interactions for many-body quantum simulation and efficient quantum computing. From a broader perspective, our work provides compelling avenues for future exploration of quantum electrodynamics and optimal control using the Floquet framework.