The FTX group shapes the physics case and develops detector technologies and concepts for future accelerator-based particle physics experiments. It has strong expertise in the preparations for a future electron-positron collider and its detectors as well as for laser-electron experiments to study Quantum-Electrodynamics in the yet unexplored regime of strong fields. PhD students in FTX become members of the PIER graduate school and through this receive offers for academic training, soft skills, and career planning. In the context of the ERC Synergy project "NP-QED", DESY will plan and conduct experiments to probe strong-field QED up to the non-perturbative regime using electron beams and intense laser boosted by plasma mirrors. The FTX group is driving the development of key parts of the experiment, designing and building the detection systems based on detailed simulations of the strong-field QED processes. Among the applications of strong-field QED is the collision of highly focused electron and positron beams in future high-energy colliders, where it influences the experimental environment in terms of background conditions and the luminosity spectrum.