By default the module will only render 50 dynamic checkboxes, but you can raise this ceiling by setting the "count" param.
This param isn't mentioned in the normal Sideview Utils docs page for Checkboxes, but if you click the link that says "Read the specification for the Sideview module: Checkboxes and its params.", those specification pages always list every param and their descriptions, so you can read about it there.
Is there any technique that i can use to add a button to check/uncheck all checkboxes?
I would wait until Sideview Utils 2.7, coming out soon, wherein I've made it so you can have a ValueSetter set REPORT to "*" upstream, and your Checkboxes will select all.
There is technically a really janky way -- Use a postprocess search to make a giant concatenated string of all the values, use ResultsValueSetter to pull down that string, use ValueSetter to split it into an array-valued key in the UI. If you do stitch all of this in between Checkboxes and its Search, and that ValueSetter has the same name as the Checkboxes module it'll populate them all. Like I said, janky!