No more pain, my friend.
Vic comes to your rescue :-)
https://youtu.be/eHpmk3R7Ifk

If I got one sub for every LR optimizing video and article I've seen over the years I could fund Adobe to finally sort it out. 

LR is an old software, not optimised for multi-core computers. So it does have issues.
But there is nothing on the market that can even remotely compete with LR plus PS.
By taking the steps I point out in the video it is possible to use it even with very heavy workflows

You can solve everything by getting the top of the line iMac for a pinch over $10,000

You don't really need a top of the line computer, just plenty of RAM and a couple of drives with a fast one.
Well, photo post processing is one of the most demanding tasks for computers. Even more for video and gaming