after previous post Script setValue based on the values of column based on value of other column matching reference

where i collected sheet IDs, currently almost 300

im trying to edit ALL those spreadsheets from theirs IDs

function update()
{
  const ss = SpreadsheetApp.getActiveSpreadsheet();           // Source spreadsheet
  const src = ss.getSheetByName('Relação');                   // Source sheet

  const LR = src.getLastRow();

  const Target_Id = src.getRange("B2:B" + LR).getValues();    // Target IDs

  for (var i = 0; i < LR; i++)
  {
    if ( Target_Id[i] !== "" )                                // check to skip "" rows
    {
      var ss_t = SpreadsheetApp.openById(Target_Id[i]);       // Target spreadsheet
      var trg = ss_t.getSheetByName('Config');                // Target sheet

      trg.getRange("B24").setValue("TEST");
    }
  }
}

and it works untill one row in column B is "" blank

Exception: Invalid argument: id
update  @ script.gs:14

aparently my check

if ( Target_Id[i] !== "" )

isnt working the way i tried, dont really understand why, thats my main question

question 2: as i tested, i know since im trying to update almost 300 sheets, im gonna run into another problem

Exceeded maximum execution time

to update everyting is going to be slow, hit that error around ID 40, so is there a way to optimize the process so i can be able to update all spreadsheets? for now im tying to just update 1 cell, as proof of concept, end goal is entire sheets with formulas, formating, etc but thats a topic for future post if needed