I have already install Magento 2 Shop by Brand, but now when I apply it for the mobile interface, it is not working so well. Do I need to purchase a PWA extension so that the mobile website will work well? Or there are any alteration I can make to help the mobile version look better?
I believe the best way to optimize the Shop by Brand extension is to add one distinct PWA Shop By Brand addons.
Normally PWA feature offers the most similar factors of a native mobile application for mobile users. Therefore, Magento PWA For Brand Addons supports your businesses in delivering a magnificent mobile shopping experience.
This extension also delivers professional brand pages with all essential information such as brand logo, description, hot products, or product status that are well displayed on any smart device.
I believe this will be the best solution for you at this moment.