Creating Change Management in SharePoint

Forms SharePoint Online
2

Dear @IT.Joe,
What is possible exactly? I am not sure that I follow. Restrict a date picket in a Date field? Sure, our date picker is based on kendo.ui.DatePicker and a lot is possible - Configuration, methods and events of Kendo UI DatePicker | Kendo UI for jQuery

For example, this code prevents dates earlies than today:

fd.spRendered(function() {
    fd.field('Date1').widgetOptions = {
        min: new Date()
    }
});

As for matrix and what not - I am not sure, but if it's a SharePoint list, you can rertrieve data from another list with pnpjs and use it in your calculations - Unable to get List Items with CAML Query - #2 by mnikitina