Can’t create directory – read only

I have the game Starruler 2 installed, I can not create a directory or write into the mods directory.

Path is /Snap/starrruler2/36/starruler2/mods

I have tried changing the permissions using krusader as root user. I have tried using chmod command but I get a read-only error. I might not be using the write options.

Any help would be appreciated