Constant issues with Lightroom Classic

Hi, can anyone help please? Ever since LR separated to the cloud version and Classic I've had issue after issue. I run High Sierra OS. Common problems: frequently showing random blank (greyed out) thumbnails; showing thumbnails with black circles and ! inside; showing all thumbnails greyed out; now crashing my MacBook pro  frequently - 6 times in the past couple of hours. (BTW,  use CC on subscription).

Am completely sick of LR. Ive spent hours on to support who tell me that it's sorted and 'will never happen again' - rubbish!

Also say it's my Mac not LR, but everything else, ALL other apps work fine, it's only EVER Lightroom that causes this. What other software do people use? (I only use PS for simple edits and then send image back to LR - which by the way, often doesn't have the edited TIF image there without shutting down LR and reopening it)

Someone PLEEEEASE help, am so sick of the hours wasted...

Thanks in advance .. (and desperation)