Can someone please suggest me where I can get inspiration before I apply Theme designer?
Does Samsung has desktop version Galaxy theme?
Just want some inspiration so that I don’t design same like other designers 
Also, does it has to be designed in photoshop? Can Samsung accept Figma files?
There is an old outdated video in the main page where a guy explains the criteria and advices on how to submit a proposal. The main idea is there, although the icons he shows as good example are horrendous. I don’t think he is a designer but at least he is like a presenter. Use your own illustrations (no stock photos) and good icons, plenty of inspiration on tik tok and other design communities.
Galaxy Themes is a web tool and you can use any software to create images yes, if they produce standard file formats such as jpg, png, gif, mp4, etc. The GT tool only works online and you can save few projects in the Samsung server but also in your computer. You’ll have access to that tool once you’re approved as seller