Cubase 14 doesn't offer any menu commands for accessing the individual automation lanes on each track. Would be awesome if you could scroll through and delete the all the automation on a particular lane, or mute a lane, or lock a lane, with single key commands.
I do not use Cubase, but I have looked into this and it appears that the application is woefully lacking in key shortcuts that could help here. Therefore your macro might have to use a last-resort option such as click at found image, or, if the screen contents are static enough, perhaps just click at the same X-Y co-ordinate each time.
Just for comparison: Logic Pro offers the following relevant shortcuts, so nag Steinberg or consider alternatives if you are as frustrated as I would be if I had to mouse around to delete automation... but I doubt that you are...