After installing the J4 Kinvara template with example files, the J51-ImageHover Gallery Module 2.1.3 works. not right.
For one thing, the column splitting doesn't work properly. The lightbox is also not displayed. Only the enlarged image is displayed in the same window....
An update of the IHG module from another J4 template (also version 2.1.3.) fixes the problem.
Joomlaversion 4.2.5. / PHP 7.4.