Hello and thank you for taking the time to report this issue. Though iOS 14 is still in Beta, we are already working on improvements to ensure Lightroom works smoothly on this OS when it releases.
I think the problem you mention is that the Import screen can look blank/empty if one chooses "Select Photos" vs "Allow Access to All Photos." Am I correct that you are asking about this import screen problem?
If so, the workaround for this is to: 1. go to iOS Settings > Lightroom > Photos
2. please choose "All Photos" (and do NOT choose "Selected Photos")