Adjustment Brush - lag makes tool unusable

I have been experiencing terrible lag when attempting to use the abjustment brush. In fact it has made the tool completely unusable. I have read through various support threads both here and elsewhere and tried all of the recommended changes, from restrictinf the video cache, turning off loop previews, not writing to XMP,  and pausing syncing, etc. but to no effect.

I am running the 10.2 release of LRC on my high-end macbook pro (specs below)

I have tried a lot of different things but nothing seems to affect this issue.

It may be worth noting that I am having a similar problem with the brush tool in photoshop as well.

Thanks for your help!

Here are my machine specs:

Mackbook Pro (15-inch Mid-2018)

Processor: 2.9 GHz 6-Core Intel Core i9

Memory: 32 GB 2400 MHz DDR4

Graphics: Radeon Pro 560X 4 GB