Batch straighten horizon

If you want images to receive some operation(s) automatically by default, such as horizon straightening: this operation(s) can be saved into a develop preset (checking only the required aspects selectively; the preset can leave all other settings alone).

Then this develop preset can be chosen to apply during import.

Or, this operation can be included in a develop preset which is set to apply as the default processing for this particular camera / file type combination. 

Or, this develop preset can be applied to highlighted images in bulk after the fact.

I would recommend a suitable Upright mode, rather than going for the tool within Crop - probably ‘Level’ if you want to permit horizon levelling only, or could be ‘Auto’ if you also want vertical convergence correction.

In my experience correction will be relatively mild: LRc won’t force it overhard, to the point of being pictorially unnatural. Not unless you choose ‘Full’, which is a special-purpose option IMO.