I have added some code that will force a minimum resolution much bigger than you're describing that'll hopefully fix this issue for next update. If you want to attempt to fix it now instead of waiting for the next update, can try to find the file on your system that is incorrectly telling the game to open this way. Not going to claim to know what I'm doing, this is an answer I got from ChatGPT by asking a question related to the issue you described and can hopefully help you:
On Linux, Unity saves display settings in a hidden file at:
~/.config/unity3d/Zingy/AmeliaStrandedAdventure/prefs
The ~ symbol means your home folder (e.g. /home/yourname/). If your game window looks very small or blurry, try deleting this prefs file to reset resolution and fullscreen settings.
You may need to enable "Show Hidden Files" in your file browser to find the .config folder.