Hi,
Have you tried connecting headphones to check that it is a speaker problem and not a left channel audio problem?
If it is a speaker problem, here’s a link to the [https://topics-cdn.dell.com/pdf/inspiron-15-7567-laptop_service-manual_en-us.pdf|service manual] for your laptop, taken from this [https://www.dell.com/support/home/au/en/aubsd1/product-support/product/inspiron-15-7567-laptop/manuals|webpage].
Scroll to p.60 to view the necessary pre-requisite steps and then the procedure to remove/ replace the speakers.
Replacement speakers are available online. Just search for ''Dell Inspiron 15 gaming 7567 speaker part'' to get results for suppliers.
Here’s a link to just one [https://www.ebay.com/p/Dell-Inspiron-7567-Left-and-Right-Speaker-Set-MM8P6-0mm8p6/755589126|supplier]. It is shown only to give you an idea of the cost of the parts. There are other that may suit you better.