Sure, if you want.
Just make sure you copy the relevant template from wppizza/templates/ to your theme directory (or preferably child theme directory if used) and edit those, so you don’t loose your edits when the plugin gets updated. Make sure to read the comments in the relevant files.

Preferably though – if at all possible – I would suggest to use css and/or some of the action hooks provided to be able to take advantage of any possible future updates or improvements of those templates.
(see https://www.wp-pizza.com/topic/customising-the-css/)

I would also recommend you choose the closest template to what you want to achieve from the default, responsive or grid layout