Multisite & sharing the same themes

Hello, I’m working with this plugin (Multisite Language Switcher) and wondering if there is a trick to get the theme shared between sites. I’ve enabled the network theme but no styles or images are coming through. I’ve installed the Shared Network Media plugin but that’s only if you are uploading a new image within a page or post, the option of inserting an image from another site is offered. Would you need to have child themes then for each site? and separately add the images in those theme files again? So if anything changes, you’d need to change it on every language site you have setup?

Also, with this plugin and the multisite enabled, it looks like I need to setup all pages and specific plugins (like Nivo Slider) unique to that site. I cannot share those settings and configurations (like the Nivo Slider) because they are their own site with separate content and elements?

I was thinking of using this plugin because we just need a language switcher and the only thing that will change will be the language of the content, menus and other text within the site but this isn’t quite how it works, is that correct?

https://ww.wp.xz.cn/plugins/multisite-language-switcher/