If your project is not going to be fully open source, then you could use premium visual assets, does anything specific stand out to you?

https://itch.io/game-assets/top-sellers/tag-tileset

https://opengameart.org/art-search-advanced?keys=tileset&title=&field_art_tags_tid_op=or&field_art_tags_tid=&name=&field_art_type_tid%5B%5D=9&sort_by=count&sort_order=DESC&items_per_page=24&Collection=

https://www.deviantart.com/search?q=tileset

Mind be wary of the licensing and limitations imposed by artists, but pretty much all of the above assets can be used, especially if the tiles are sized 32x32 and are top-down 2d non-isometric.

Regarding pokemon style, you can certainly find similar style game tile assets on deviantart linked above, however you may run the risk of angering nintendo. That said, passing it through an AI filter or as a stable diffusion input image it could be made less in nintendo's image.

However in terms of game style, a user walks into a virtual shop, they approach an NPC and can interact with blockchain functions in a game like menu, all immediately possible without limitations.

I'd have a good look through the art assets out there, you could even get designing the store and surrounding environmental maps in tiled without any programming skills, pretty much like paint except you're placing 32x pixel art tiles

Technically, you could draw your shop's interior, exterior and surrounding area fully in photoshop and import that into your tiled map, but you would lose out on tiled tileset modularity