Need help/suggestion in updating existing values in multiple dropdown

Hi , I have a multiple dropdown inside a grid layout , so choice values for that dropdown  previously static one coming from database , but now we have changed it as cascading one based on condition the dropdown choice value will change. Now the existing request are all throwing error. I thought of based on the request created date to change the choice values to be selected but i am not sure where that condition can applied inside the dropdown choice or before , because for new request also for choice values i have applied some if condition . Its not working properly. Can anyone help me to identify the option which is efficient?

a!localVariables(
  local!fundlookup: {
    a!map(lookupId: 1, value: "Comment A"),
    a!map(lookupId: 2, value: "Comment B"),
    a!map(lookupId: 3, value: "Comment C"),
    a!map(lookupId: 4, value: "Comment D"),
    a!map(lookupId: 5, value: "Comment E"),
    a!map(lookupId: 6, value: "Comment F"),
    a!map(lookupId: 7, value: "Comment G"),
    a!map(lookupId: 8, value: "Comment H")
  },

  local!Requestmaster: a!map(createdOn: todatetime("2025-09-10")),

  local!commonFund: if(
    local!Requestmaster.createdOn < todatetime("2025-09-18"),
    remove(local!fundlookup, { 7, 8 }),
    index(local!fundlookup, {1, 7}, {})
  ),

  local!mutualFund: if(
    local!Requestmaster.createdOn < todatetime("2025-09-17"),
    remove(local!fundlookup, { 7, 8 }),
    index(local!fundlookup, {1, 5}, {})
  ),

  local!citFund: index(local!fundlookup, {2, 3}, {}),

  local!productCommentIds: {},

  a!multipleDropdownField(
    label: "Select Comments",
    choiceLabels: if(
      ri!fundType = 100, /* Dummy CIT fund type ID */
      index(local!citFund, "value", {}),
      if(
        ri!fundType = 200, /* Dummy Mutual fund type ID */
        index(local!mutualFund, "value", {}),
        index(local!commonFund, "value", {})
      )
    ),
    choiceValues: if(
      ri!fundType = 100,
      index(local!citFund, "lookupId", {}),
      if(
        ri!fundType = 200,
        index(local!mutualFund, "lookupId", {}),
        index(local!commonFund, "lookupId", {})
      )
    ),
    placeholder: "---Select Comment---",
    value: local!productCommentIds,
    saveInto: local!productCommentIds
  )
)