It's possible to change resolution in a configuration file. It should be located at C:/Users/<your_user>/AppData/Roaming/WizardsOfTheCode/Soulash/data/user_settings.json

The AppData folder might be hidden. You can edit the "viewport" part of the file like so:

"viewport": { "borderless": false, "fullscreen": false, "resolution": { "h": 1080, "w": 1920 }, "tile_dimensions": [ 32, 32 ] }

When you edit and save the file then start the game again, the changes should be applied.