There is no such setting within Photoshop or Lightroom that changes the thickness of crop guidelines or changes its color.
However this issue has been reported in our Feedback community Lightroom Classic: Overlay is very hard to see (Crop/Transform) | Photoshop Family Customer Community and our Engineers are working on it. Be sure to click the Me too button in the upper-right corner.
One thing that came out is if you uncheck the option "use graphics processor" in both Lightroom and Photoshop it might have some considerable difference to the guideline visibility.
Let us know if the above suggestion helps.