Hello, Lior.

Please, create a new ticket for each question to avoid mess.

1. I checked your store and you have a collection with the huge amount of products.

The custom filters (such filters like Vendor, Product type, Price filter etc.) work at collections with 1000 products or less - https://take.ms/MMoeC

This is a Shopify software limit for themes, you may check this form post for more details - https://community.shopify.com/c/Shopify-Design/50-Product-limit-on-collections/td-p/204693

The built-in theme filters are good for small collections with less than 1000 products.

The workaround is to use only filters by product tags. You may also split your catalog for collections with fewer products.

Or search for a filter app at https://apps.shopify.com/ for more advanced filter options and 1000+ product stock.

2. - I checked the issue on your store. And you have the missing translation there -

https://prnt.sc/16p3d7d

You can edit the missing translation at Actions -> Edit languages on your Published theme –

 https://prnt.sc/13ijrcv

Then you may need to press "filter this page" to edit missing translations –

https://prnt.sc/16p3rpr

https://prnt.sc/16p3090

https://prnt.sc/16p380i

I've added the translation in English, you may change it to the language you use.

- You may also need to navigate to Theme settings -> Colors and change either the "Base" color  -

https://prnt.sc/16p5bqg

Or color of the Label 'Pre-order' to make the text visible -

https://prnt.sc/16p5hsm

3. You can configure product images on Collection pages at Theme settings -> Product -> Collection Page -

https://prnt.sc/16p230g

Please, read more details in our user manual -

https://mpthemes.net/shella-shopify-theme/documentation-version4/doc07-10-theme-settings-product-collections.php#product-collections