Setting an appropriate user style using something like Stylus to override it should work. See how this one does it: https://userstyles.world/style/2264/unblock-algoexpert-text-...
If you can't set user styles in your browser, you might not be able to accomplish it, though.
unless the site already did that, so you'll have to out-override them by applying an id to the outer html tag and doing the ol'
#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride#useroverride * {user-select: all !important]