You can dequeue a style, for do that you can use wp_dequeue_style() or wp_deregister_style()
To use both of them, first u need to find the handler of the style you want.
Go to the plugin’s folder you wanna remove the css and search for wp_enqueue_style or the file name and locate the handler.
wp_enqueue_style( 'my-plugin-font-awesome', plugins_url('my-plugin/font-awesome.css') );
and i need to deregister or dequeue it
add_action( 'wp_enqueue_scripts', 'my_fontawesome_deregister_styles', 100 );
function my_fontawesome_deregister_styles() {
wp_dequeue_style( 'my-plugin-font-awesome' );
}
or
add_action( 'wp_enqueue_scripts', 'my_fontawesome_deregister_styles', 100 );
function my_fontawesome_deregister_styles() {
wp_deregister_style( 'my-plugin-font-awesome' );
}
OBS: the priority must be higher than the plugin’s wp_enqueue_scripts()