This study investigates the radial and temporal evolution of microturbulence in fusion plasmas using high-performance computational simulations. Turbulent transport, driven by microinstabilities, is the dominant mechanism for energy loss, degrading confinement by creating radially extending channels through which heat escapes from the plasma core. To analyze these processes, this research utilizes the IMAS framework to retrieve experimental density and temperature profiles, enabling a direct assessment of turbulence evolution during plasma discharges. The focus is on two key areas: the L-mode shortfall problem, where ion-scale turbulence is suppressed while electron-scale modes persist, leading to an underestimation of turbulent fluxes in reduced models, and the formation of the edge transport barrier (ETB) in H-mode, where strong electric fields generate steep gradients that suppress large-scale turbulence but sustain small-scale modes. To address these challenges, GENE will be extensively employed for both linear and nonlinear gyrokinetic simulations, resolving ion and electron scales to capture the full turbulent spectrum. In parallel, this work explores the interaction between fusion-born alpha particles and microturbulence, extending previous studies on JET-DTE2 to high-performance DTE3 scenarios with increased deuterium beam power. Using GENE simulations and IMAS-based reconstructions, the study assesses how alpha particle density and pressure gradients influence the excitation of Toroidal Alfvén Eigenmodes (TAEs). Comparisons with ETS output help validate alpha population estimates and their effects on confinement. By examining the interplay between zonal flow stabilization and TAE-induced transport, this work supports the development of reduced physics models for energetic particle dynamics in burning plasmas. Together, these investigations advance the understanding of the L-mode turbulence and energetic particle effects in fusion plasmas, providing critical input for improving predictive capabilities in support of ITER and future reactor designs.