OR hook up a mouse and keyboard so it could work that way, without any spoocial special input handling 👍👍👍👍
Then do whatever else
You still need to do step 5. A complete rework of everything that used the file-system API to read assets without the built-in asset loader. and step 6.
Some conditional compilation wizardry (some packages only work on Desktop and handle stuff like fullscreen, thus your gonna need to not only remove that setting on mobile, but also probably make it either not have that dependency, or, if you want to keep desktop support on top of mobile support, use import ifs to have condition compilation and make the package only be imported and used if you are compiling for desktop)