Prev/next image on the Horizontal Gallery do not work on MOBILE phone only

Hi folks. I realized I have a strange issue in my website.

The PREV (“<“) and NEXT (“>”) buttons on the Horizontal Gallery of my website are not working anymore.

If I open an image in the Lightbox, PREV and NEXT buttons on the single image are working, though.
Last time I’ve tried this was about 1 month ago, and it was working fine.

Please note:
1) The buttons were not working also before upgrading to WordPress 6.9 this morning.
2) This is very interesting: if I try on Chrome on PC, opening the Inspector and selecting one of the “iphone” sizes, these buttons are working as expected. Therefore, it’s only when trying on a mobile phone (an iphone in my case).

I’ve applied some changes to the standard behaviour of the Horizontal Galllery:
Change #1 in the CSS: I wanted to be able to open the image just by clicking anywhere on the image, and not only on the “magnify icon”. See the last CSS in this ticket, suggested by @Ismael: ticket #1358626
Change #2 in the functions.PHP: I wanted to open the images from the Horizontal Gallery directly in the Lightbox. Same ticket as above, see the .PHP file suggested by @Ismael.

I’ve also tried removing them both: still the same (wrong) behaviour, the PREV/NEXT buttons are not working.

In this video you can see what’s happening on my mobile (an iPhone).
I was browsing the page I added to the private area.

Thanks in advance, as usual.
Bye!
A.-