Yes, it is possible and very much welcome! And thanks for the offer!
In your machine you have the translation files (assuming you have the welcome package installed, and preferably up to date ).
Take file bash file /usr/share/endeavouros/scripts/translations-welcome-en.bash as the base, and translate that directly to Swedish. Save the new file to /usr/share/endeavouros/scripts/translations-welcome-se.bash. You can test the translation with command
You don’t have to change anything in the comments (except some obvious things, you’ll see). So mostly the string values should be translated.
When you are ready, please let me know!