Whenever I've created a new project in Rider and added some files to the project, Rider was asking to add these file to Git / Version control:
Ticking "Don't ask again" only helps for this project, but of course there must be a global setting.
Indeed, a setting can be found in
File | Settings | Version Control | Confirmation:
So let's create a new project and add a file, to see if this works...
Well, that didn't work... because there's another setting in
File | New Projects Setup | Settings for New Projects... (you can also use actions modal) which looks absolutely the same but it is for new projects:
If you change "When files are created" to "Do not add", you won't be asked again, I'll promise 🤞️.