This is considered the most effective "no-root" method for gamers. It uses a script to prevent the CPU from scaling down. Termux is an Android application.
⚠️ : Maxing out all CPU cores on a shared system may violate fair-use policies. Use only on your own hardware or with permission. download max all cpu core no root top
Even if you were able to achieve this (via rooting or a specific device exploit), forcing all CPU cores to run at maximum frequency 100% of the time is generally a bad idea for the following reasons: This is considered the most effective "no-root" method