Hello,
1) Choose the sort order by Date and Asc/Desc depending on new or old products to show first.
2) Follow the multivendor plugin docs https://wc-marketplace.com/faq/how-to-remove-more-offers-tab-in-the-single-product-page/
3) Watch video tutorial https://youtu.be/7QluEYxznKs but use Elementor to edit static blocks https://xstore.helpscoutdocs.com/article/47-static-blocks
Regards