In this answer I've changed colors of search icon, search hint icon, close icon, plate, query hint color, query color
view!!.findViewById<EditText>(
            searchView.context.resources.getIdentifier(
                "android:id/search_src_text",
                null,
                null
            )
        ).apply {
            setTextColor(ContextCompat.getColor(context!!, R.color.darkThemeIconColor))
            setHintTextColor(ContextCompat.getColor(context!!, R.color.colorAccent))
        }
        view!!.findViewById<ImageView>(
            searchView.context.resources.getIdentifier(
                "android:id/search_button",
                null, null
            )
        ).imageTintList = ColorStateList.valueOf(
            ContextCompat.getColor(context!!, R.color.darkThemeIconColor)
        )
        val mDrawable = SearchView::class.java.getDeclaredField("mSearchHintIcon")
        mDrawable.isAccessible = true
        val drawable = mDrawable.get(searchView) as Drawable
        drawable.colorFilter = BlendModeColorFilterCompat.createBlendModeColorFilterCompat(
            ContextCompat.getColor(context!!, R.color.darkThemeIconColor),
            BlendModeCompat.SRC_ATOP
        )
        view!!.findViewById<ImageView>(
            searchView.context.resources.getIdentifier(
                "android:id/search_close_btn",
                null, null
            )
        ).imageTintList = ColorStateList.valueOf(
            ContextCompat.getColor(context!!, R.color.darkThemeIconColor)
        )
        view!!.findViewById<View>(
            searchView.context.resources.getIdentifier(
                "android:id/search_plate",
                null, null
            )
        ).backgroundTintList = ColorStateList.valueOf(
            ContextCompat.getColor(context!!, R.color.darkThemeIconColor)
        )