I'd like to chime in on this as a bit of a tech-saavy enduser experience.
I explicitly use the itchio desktop app specifically to keep things 'like Steam' where everything is installed within a specific directory OUTSIDE of Program Files and there are no extra shortcuts or other crap (like registry editing) being necessary for installation/execution of the game itself.
I absolutely despise those inno setup and other 'setup' programs because they often make forced unchangeable default presumptions about a user's computer without properly informing/disclosing what is going to be installed/changed during the process. Uninstall issues have also been an issue with certain games that utilize this method of installation.
Please just use Butler and make your game 100% self-contained without needing 'installation' through a setup program or whatever.
Also please remember that installation to Program Files is a BAD idea unless you are Microsoft, AMD, Nvidia, or another hardware manufacturer installing drivers. You'd think with Windows XP being deprecated for ~2 decades now that game devs would've caught up with the times and how restrictive the Program Files directory permissions are by (security) design. Many users install to a separate hard drive for games while others may use a separate partition. Furthermore, there are built-in system variables for a REASON. Instead of hard-coding a path like C:\Program Files (x86) or whatever, you may want to use %PROGRAMFILES% or %PROGRAMFILES(X86)% instead. There's a handy list here: https://archive.fo/90HNY