Hi @ethanhunt ,
The best way (but not the quickest) is to replace the keyboard.
You can cause more problems than what you had when trying to repair keyboards.
They are not that expensive to replace.
Just search online for ''Dell Inspiron 15-7548 keyboard'' to get results for suppliers.
Here’s a link to the [https://downloads.dell.com/manuals/all-products/esuprt_laptop/esuprt_inspiron_laptop/inspiron-15-7548-laptop_service%20manual_en-us.pdf|service manual] for the laptop, taken from this [https://www.dell.com/support/home/us/en/04/product-support/product/inspiron-15-7548-laptop/manuals|webpage].
Scroll to p.57 to view the necessary pre-requisite steps and then the procedure to remove/replace the keyboard.