Google Sheet App Script For next LOOP error [closed]

Want to generate a loop for picking next symbols from Table A in Sheet "RANK!R9:S".

Then want to copy every next row symbol to "PF Sheet!B20" (cell only) for 1st Loop. This is going to generate a new set of values in "PF Sheet!D16:D", for each value copied to "PF Sheet!B20" cell.

Pl. refer the google Sheet link

https://docs.google.com/spreadsheets/d/1r0_oHLTcT9tmTJPgKVgkGwGWhooBM8uluwmWcC92eOk/edit?usp=sharing

function permutation() {

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var rank = ss.getSheetByName('Rank');
  var pf_sheet = ss.getSheetByName('PF Sheet');

  var symbols = pf_sheet.getRange('B20')
  var start = rank.getRange('S9');
  var end = rank.getRange('S4');
  
  rownum = start.getRowIndex()
  rowTarget = end.getValue()

  for (let i = rownum; i <= rowTarget; i++) { 
    var value = rank.getRange(i+1,19,).getValue();
    value.getValue().copyTo(symbols());

    // wait to complete all the changes on the spreadsheet
    SpreadsheetApp.flush();

    var start_2 = 2 
    var end_2 = pf_sheet.getRange('D10').getValue()

    for (let i = start_2; i <= end_2; i++) { 

     Logger.log(symbols,start_1)   

    }

  }

}

Error Line 16