I have created a multi-store in Prestashop (1.7.5), the problem is that every time I add a new store to the multi-store it is created without any style or functionality, I will attach a photo of how it looks at the moment.

I have done the following without success so far:
Verify that all theme files and images are in the server folder so they can be accessed and consumed.
Set permissions of 755 to all folders and 644 to all PrestaShop files as indicated in the official documentation.
Likewise, although not recommended, I have given 777 permissions to the entire Prestashop folder but it is not solved in any way.
First things to try would be to clear the cache and toggle "friendly urls" - both of these can cause random stupidness. I'm not an expert on multistore though so maybe others could recommend additional steps.
I assume you're not seeing any errors in the logs - which makes me assume it's probably related to the .htaccess file (friendly urls in PrestaShop speak) and/or cache.