Great idea @ClSlaid 

Thanks to @AbrarNitk we have a first version of LogicalPlanBuilder::from(arc_input) in #10466 🙏

Now that we have merged that PR we can make a second PR (and maybe a second ticket) about switching the internal representation from

To

 pub struct LogicalPlanBuilder { 
     plan: Arc<LogicalPlan>, 
 } 

The rationale is as explained by @ClSlaid on #10465 (comment) -- that in some cases this can prevent cloning the input

Originally posted by @alamb in #10465 (comment)