We recently had an ask to limit the number of columns that could be selected, and were not able to find an out of the box solution (nor was support).

Something like this would be great, which is the same implementation as the kendoGridFilterMenuTemplate which allows you to override just the content of the column chooser, and not have to manually create your own menu entry by overriding the whole kendoGridColumnMenuTemplate

<ng-template kendoGridColumnChooserMenuTemplate let-service="service">
    <our-custom-chooser-component></our-custom-chooser-component>
</ng-template>

or, alternatively, if we were able to specify a grid parameter for a max number of columns as a grid level [maxColumns], that would work as well.