Start with Franco Kernel Manager . It is the safest entry point. If you want to go deeper, set up Shizuku and find an app that modifies governors via that method.
Android devices are designed to save battery. To do this, the system "throttles" the CPU, meaning it slows down the clock speed or parks cores when they aren't in heavy use. To "max out" your cores without root, you essentially need to tell the Android OS to prioritize performance over battery life. Best "No Root" Apps for CPU Optimization max all cpu core no root apk download
Historically, changing CPU governors or frequencies required root because you needed access to the /sys/devices/system/cpu/ directory. However, developers have found workarounds using Android’s native and specific permissions granted via ADB (Android Debug Bridge) or accessibility services. Start with Franco Kernel Manager