The calibration section is only still there in Classic as a legacy option to support files edited in very old Lightroom versions I think where this was used to do some corrections that were not possible otherwise. I think they currently want you to do this just using profiles.
I highly doubt Adobe will ever add this to Lightroom (the cloud version). If you need it, use Classic to do the small changes and save the change as a profile and use the profile in Lightroom cloud or do it in dng profile editor. Best place to ask for features is https://feedback.photoshop.com . This forum is user-to-user and there are very few engineers from Adobe here that could affect change.