@Mark Philips

Hey,

enter corename Magento_Checkout to Magento_Checkout-- at app\design\frontend\vendor\theme\ location 

and run below command

php bin/magento s:up php bin/magento s:s:d -f php bin/magento c:fde here 

And check minicart is load or not, if its not working please share the screenshot or the URL, so we can check from our end also.

Thank You!

Enter corename Magento_Checkout to Magento_Checkout-- at app\design\frontend\vendor\theme\location

and run this command:

php bin/magento s:up php bin/magento s:s:d -f php bin/magento c:fde here 

Then, check if the minicart is loaded.