This study demonstrates the generation of high-energy proton beams with a spectrally separated high-energy component of up to 150 MeV using laser-driven ion accelerators. The experiment involves irradiating solid-density plastic foil targets with ultrashort laser pulses from a repetitive petawatt laser. The preceding laser light heats the target, leading to relativistic-induced transparency upon the arrival of the main pulse. This triggers proton acceleration through a cascade of different mechanisms, as revealed by three-dimensional particle-in-cell simulations. The transparency of the target, which can be measured by the transmitted laser light, serves as a feedback parameter for automated laser and target optimization, enhancing the stability of plasma accelerators. The results mark an important milestone in the field of plasma accelerators, paving the way for various demanding applications, including radiation therapy and advanced accelerator concepts.This study demonstrates the generation of high-energy proton beams with a spectrally separated high-energy component of up to 150 MeV using laser-driven ion accelerators. The experiment involves irradiating solid-density plastic foil targets with ultrashort laser pulses from a repetitive petawatt laser. The preceding laser light heats the target, leading to relativistic-induced transparency upon the arrival of the main pulse. This triggers proton acceleration through a cascade of different mechanisms, as revealed by three-dimensional particle-in-cell simulations. The transparency of the target, which can be measured by the transmitted laser light, serves as a feedback parameter for automated laser and target optimization, enhancing the stability of plasma accelerators. The results mark an important milestone in the field of plasma accelerators, paving the way for various demanding applications, including radiation therapy and advanced accelerator concepts.