Lightroom Classic CC import is AWEFULLY slow and mostly stalls completely and/or Lightroom crashes

Sorry to open yet another bug-report thread since the last one is 7 month old, and even the other one from 2016 is still open and unreplied...!

Importing photos and videos (Canon RAW and MP4 from a Canon EOS 650D here) was already awefully slow in 7.1 since over a year now, but still usable. I finally updated and hoped, and I was desperately disappointed to see that the import now even won't end anymore.

I'm running this on a Intel i5 2500k@4.4GHz, 16GB RAM (XMP profile), GTX970, Windows7 x64 on a SSD (about 490MB/sec).

Symptoms: 

• on import (after selecting all photos and give them a common tag, pressing the "import" button) nothing seems to happen
• the progressbar stays at 0%
• if I click on anything the whole Lightroom-window greys out and I get the Windows7 unresponse-window asking me to wait or close the application
• If I check the Windows7 ressource-monitor there is nothing that is stealing either RAM nor CPU-time
• if Lightroom still copies files, it is awefully slow (<0,5MB/sec) without ANY sign why

This is NOT a hardware-issue, nor a OS or third-party software issue. This is CLEARLY in the ballpark of Adobe, since more than 2 years now and the only thing that Adobe is capable of is making this software worse and worse, this is garbage. Odd that Adobe isn't even listening to their pro-customers in ANY way. :(

This is completely unacceptable.

Sorry guys if this was too much ranting, but so much ignorance has to get some kind of answer. I also made the important facts bold for the not listening customer-support.