No pagination in Elsevier journals
Page numbers are going to go away because (i) stuff isn't actually printed any more, and (ii) page numbers are inconvenient in the publishing process because one needs to know how many pages the articles before the current one have before giving the current one page numbers. So the short answer is: You'll need to learn to cope with it.

In similar situations, I've used the following formats to indicate how many pages an article has:


  W. Bangerth: "Stuff more scientists ought to talk about", Journal of Important Research, article 12687 (24 pages), 2019.


or


  W. Bangerth: "Stuff more scientists ought to talk about", Journal of Important Research, vol. 24, pp. 12687/1-24, 2019.