How to apply a specific user preset to a batch of photos in Grid mode in Library section ... this option aren't present.
Use the Saved Preset dropdown in the Quick Develop panel on the right.
i find this way ... so is not very user friendly!
It's the same number of mouse clicks to invoke from the right-click menu or from the Quick Develop panel. You can collapse the Quick Develop panel to save space, and the presets dropdown will still be visible.