We wish you a very happy new year and we are sorry about the experience with Lightroom.
Would you mind sharing the version of Lightroom you are working with along with the operating system you are using? Have you tried disabling the Graphics processor from the Preferences of Lightroom to check if that helps? If not, please go to the Preferences of Lightroom, then Performance and disable the option to Use Graphics processor and relaunch Lightroom to test if you notice any difference.
I do not work for Adobe, have no connection to the company whatsoever, do not know any Adobe employees. And, believe it or not, I'm not responding to you in defense of Adobe or Lightroom. And I don't doubt that you are experiencing performance issues on your computer. Unfortunately, performance seems to be an individual issue that is difficult to isolate. If that was not true then Adobe would have resolved the issue years ago. For instance, I'm still using an old HP Pavilion desktop computer that is probably close to 10 years old. It was purchased with Windows 7 installed after Windows 8 was introduced. I have since "upgraded" to Windows 10, it has 8 GB RAM, no graphics card (just onboard graphics on the motherboard). I really have no performance issues with either Lightroom Classic or Lightroom. I realize that doesn't bring you any comfort nor does it solve your issue. But there are so many different computer configurations, and so many components that can conflict and create problems that it seems difficult to isolate where the performance issues creep in. I realize that slowness is killing you. However, I am confident that Adobe is doing whatever they can to improve performance. But they cannot possibly build computers that replicate every possible configuration that exists.