To disable savehist-mode, which is a global minor-mode, one can use: (savehist-mode -1) When disabling savehist-mode, the function savehist-uninstall is called ... savehist-minibuffer-hook is removed from the minibuffer-setup-hook, and savehist-autosave is removed from the kill-emacs-hook, and the timer savehist-timer is canceled.
However, savehist-mode is not enabled in Emacs 26 by default. Therefore, the better approach would be to find out where in the user-configuration of the original poster savehist-mode is being enabled and remove that line of code or comment it out. The easiest method would be to use grep and search for the term savehist-mode.
savehist-mode has been around for ages and it is highly unlikely it is responsible for making Emacs freeze frequently. Turning it off for purposes of troubleshooting, however, may be a worthwhile endeavor.
The best approach is to try and get a backtrace when Emacs freezes. If pressing C-g does not suffice, then consider building Emacs from source and launching Emacs under gdb ... with the terminal starting directory being the src directory so that the .gdbinit gets loaded. Then, when Emacs freezes, you can force a backtrace ... which is beyond the scope of this answer.