If you sign into your same Lightroom account at https://lightroom.adobe.com/, the LR Web app does have a slideshow feature. Go inside an album/collection, select the 3-dot button at the top right and you will see Slideshow
The Lightroom app for Apple TV also has a slideshow feature.
Thanks for that. I know that LrC has this slideshow feature, but it seems that Lr does not. I use Lr on both my mobile devices & on a Windows 10 desktop & the slideshow is available on the mobile devices but not on the desktop. I wonder why?
— — “My religion is kindness”. - His Holiness the Dalai Lama