I had dozens of photographer friends try importing their multi TB photo libraries into different Linux systems using all kinds of photo management software. They all choke. Shotwell is the most stable but even it will crash every few few weeks and that would periodically require reimporting all the photos again...
My library is only 50k raw files, and Lightroom is not exaxtly fast either. Browsing the library, scrolling, etc. is sluggish. On a powerful workstation, 24 threads, 128gb ram, etc