Calling field by computed name

Hi, I need Ninox to copy a content of specific field by computed field name. Ninox need to choose a field which contains an index of month. Lets say that I create a report fo january (index = 1). Field name is '1 - Plan'.. So there are 12 fields for 12 months.. I tried something like this.. Is it possible to call a field by computed name?

Last part of this formula is '1 - Plan' but I want it to be computed so that I don't have to make 12 rows of if, if, if.. Hope you understand my questions.. Thank's..

let D := 'Date';
let IM := month('Date');
number(if Interval = 1 then
if IM = 1 then
(select 'Reports')[text(year(D)) = text(Obdobje)].'(IM+" - Plan")' else.....