Can't select objects

Most problems with LR's AI commands are caused by older, buggy graphics drivers. Try updating your graphics driver by going directly to the manufacturer's web site:
https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.html#solution-4

If that doesn't help, please copy/paste here the entire contents of the LR menu command Help > System Info -- that will let us see exactly which versions of hardware and software LR thinks you're running.