Without more detail on what it actually looks like, I'm going to make some suggestions based on assumptions.
Are "formative" and "summative" categories in your Infinite Campus gradebook? I don't use IC, but you can set up grading categories in Canvas that will then sync to whichever categories you want in your other gradebook.
In general terms, formative work shouldn't count in the student gradebook. You can approach this two ways:
- Set up weighted gradebook categories with formative at 0% overall course weight and summative 100% overall.
- Exempt formative assignments from the final score (assignment by assignment).
Method 1
In Assignments, click on + Group to create a new assignment group and title it either Formative or Summative. Then, click on the three-dot menu in the top right and select Assignment Groups Weight. This will allow you to set percentage weights for each category respectively. Then, follow your district's guides for how to set up a sync to IC.
Method 2
Create whatever gradebook structure you want but make sure to remove your formative assignments from the final calculated score.

This way, all of your assignments can still go into the book but only the summative tasks, regardless of scoring category, will count for that final grade.
Again, this is working off of several assumptions, but it might get you closer to what you're trying to do without having to wait for a feature option to be selected and implemented.