Those desks are nice if you don't need any file storage at all. I think it would be helpful to start with a design inspiration. Given the desks you selected and your posters, maybe something like this can serve as inspiration. I think the blue walls would look great with your posters, and the desk is similar in style. [[(https://www.houzz.com/photos/rough-hollow-parade-home-contemporary-home-office-austin-phvw-vp~202111) [Contemporary Home Office[(https://www.houzz.com/photos/contemporary-home-office-ideas-phbr1-bp~t_732~s_2103) by Austin Interior Designers & Decorators PPDS Maybe something more feminine like the soft powder blue...here they use a dresser as a storage unit behind the desk. [[(https://www.houzz.com/photos/nest-home-office-eclectic-home-office-boise-phvw-vp~70149) [Eclectic Home Office[(https://www.houzz.com/photos/eclectic-home-office-ideas-phbr1-bp~t_732~s_2104) by Boise Interior Designers & Decorators Judith Balis Interiors [[(https://www.houzz.com/photos/pella®-350-series-casement-window-traditional-home-office-cedar-rapids-phvw-vp~1427906) [Traditional Home Office[(https://www.houzz.com/photos/traditional-home-office-ideas-phbr1-bp~t_732~s_2107) by Other Metro Windows Pella Windows and Doors It would also be helpful to do a room layout so you can play with how and where and what size furniture might work for you. I've played with homestyler.com. It's free on line and seems relatively intuitive to use. You can also think about window treatment...if you want a fabric one, the fabric would need to coordinate with your poster colors. Or you could use something like a woven wood blind which is more neutral.

As mentioned above, measure space and I think you may want a settee for its back support vs a bench. Decide on an armless style or not, length, and the color and then start your search. If not shopping in person, be sure to read reviews around comfort and durability

To hide cords, consider adding the equivalent of a "backsplash" to the desk but with a space between desk top and cords to disappear into so they can reach a multiple electrical outlet attached to the back of the desk. One plug from the multiple outlet will need to reach an outlet. Cords from desk top items will still be seen behind the items between those items and the "backsplash" They'll still be visible. If you drill holes in a solid "backsplash" board, you'd hide more of the cords. I've also seen basic desks with holes in the top of the desk at the back edge and the outlet hidden beneath the desk ... as this one appears to have: https://www.madisonliquidators.com/item/l-shaped-desk/4888/?adid=514792310094&gclid=EAIaIQobChMIiPO61aui8gIVFfjICh1t1QTwEAQYByABEgJt_PD_BwE Such desks usually have rolling filing cabinets or drawer/file units with shelves and/or drawers to set beneath the desktop by each side wall of the desk. https://www.harperoffice.com/onyx-mesh-open-mobile-file-two-drawers-15-3-4w-x-17d-x-27h-black--2?gclid=EAIaIQobChMImJysmKyi8gIVWsDICh2DzADJEAQYAyABEgIx9PD_BwE Others have storage built in as a part of the desk. https://www.wayfair.com/17-Stories--Sproul-LShape-Executive-Desk-X114267104-L32-K~W003156093.html?refid=GX528945859912-W003156093&device=c&ptid=910691620078&network=g&targetid=pla-910691620078&channel=GooglePLA&ireid=113112265&fdid=1817&gclid=EAIaIQobChMIiPO61aui8gIVFfjICh1t1QTwEAkYBiABEgIYMvD_BwE

Im not a designer, but i think the least expensive option is to make that passthru wider and lower it to counter height. i would remove the wall to the hearth room/dining room. now you will have the look of an open kitchen your hearth room could now be your dining area and your new passthru could have an extended countertop for seating in the old dining room.