For a case.. one of these is great. basically you need a 17 inch laptop sleeve. just make sure you check the inside dimensions.

https://www.amazon.com/gp/product/B01C8H1VX2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

There are not many choices in that size, but shop around you might find one with more outside pockets.

For a pen case, get a fountain pen case. there are tons of great choices.

https://www.amazon.com/Pencil-Holder-Executive-Fountain-Stylus/dp/B01FZ9Q5WW/ref=sr\_1\_31?dchild=1&keywords=fountain+pen+case&qid=1631552694&sr=8-31

i have the same one from amazon Kuuqa Black Hard Pencil Case EVA Hard Shell Pen Case Holder for Executive Fountain Pen and Stylus Touch Pen https://www.amazon.com/dp/B01FZ9Q5WW/ref=cm_sw_r_cp_api_i_PxN6AbBZHFGJ0