Separate script for multiple google sheets

I have google sheet. There are two sheet named "Subjects" and "Subjects_Classes"

I have written a script for sheet "Subjects" as follows:

const ss = SpreadsheetApp.openByUrl("https://docs.google.com/spreadsheets/d/.../edit?usp=sharing")
const sheet = ss.getSheetByName("Subjects")
function doGet(e){
  let obj = {};
  let data = sheet.getRange("A1:B1000").getValues();
  obj.content = data;
return ContentService.createTextOutput(JSON.stringify(obj)).setMimeType(ContentService.MimeType.JSON)
 
}

I am processing the same with Javascript in html as follows: It is working perfectly.

fetch('https://script.google.com/macros/s/AKfycbxAlLPXi0Knsl1xEUQGpyUgZ26oeVtlLlajiHHGc9sMHMjkg9WKZigqUvbRiunkcA1UwQ/exec')
    .then(res => res.json())
    .then(data => {
        let subjectsdiv = "";
        data.content.forEach(item => {
            if (item[0] === "") {
                // skip to the next iteration if item[0] is empty
                return;
            } else {
                subjectsdiv += `<div class="col">
                                  <div class="card h-100">
                                    <img src="#" class="card-img-top img-responsive" alt="...">
                                    <div class="card-body">
                                       <h5 class="card-title">${item[0]}</h5>
                                       <p class="card-text">Explore the many ${item[0]} resources available online to enhance your understanding of the subject</p>
                                    </div>
                                    <a href="${item[1]}" class="btn btn-primary stretched-link" target="_blank">Read</a>
                                  </div>
                                </div>`;
            }
        });
        document.querySelector("#Subjects").innerHTML = subjectsdiv;
    });
    
</script>

Now I need another JSON for sheet "Subjects_Classes" as follows: Hence Sheet and columns are different.

const ss = SpreadsheetApp.openByUrl("https://docs.google.com/spreadsheets/d/ ... /edit?usp=sharing")
const sheet = ss.getSheetByName("Subjects_Classes")
function doGet(e){
  let obj = {};
  let data = sheet.getRange("A1:C1000").getValues();
  obj.content = data;
return ContentService.createTextOutput(JSON.stringify(obj)).setMimeType(ContentService.MimeType.JSON)
 
}

I need help to create script for another sheet. Also need help to access the same in html (if changes is required).

Although I'm not sure whether I could correctly understand your expected situation, how about the following modification?

In this modification, the spreadsheet and range are changed using a query parameter.

Google Apps Script side:

Please set your Spreadsheet ID and range to object.

function doGet(e) {
  const object = {
    pattern1: { spreadsheetId: "###", range: `'Subjects'!A1:B1000` }, // Please set your Spreadsheet ID and range.
    pattern2: { spreadsheetId: "###", range: `'Subjects_Classes'!A1:C1000` }, // Please set your Spreadsheet ID and range.
  };
  if (object[e.parameter.pattern]) {
    const { spreadsheetId, range } = object[e.parameter.pattern];
    let obj = {};
    let data = SpreadsheetApp.openById(spreadsheetId).getRange(range).getValues();
    obj.content = data;
    return ContentService.createTextOutput(JSON.stringify(obj)).setMimeType(ContentService.MimeType.JSON)
  }
  return ContentService.createTextOutput(JSON.stringify({content: []})).setMimeType(ContentService.MimeType.JSON)
}

Javascript side:

Please set your Web Apps URL including the query parameter like ?pattern=pattern1 or ?pattern=pattern2 like https://script.google.com/macros/s/###/exec?pattern=pattern1.

From:

fetch('https://script.google.com/macros/s/AKfycbxAlLPXi0Knsl1xEUQGpyUgZ26oeVtlLlajiHHGc9sMHMjkg9WKZigqUvbRiunkcA1UwQ/exec')

To:

fetch('https://script.google.com/macros/s/AKfycbxAlLPXi0Knsl1xEUQGpyUgZ26oeVtlLlajiHHGc9sMHMjkg9WKZigqUvbRiunkcA1UwQ/exec?pattern=pattern1')

or

fetch('https://script.google.com/macros/s/AKfycbxAlLPXi0Knsl1xEUQGpyUgZ26oeVtlLlajiHHGc9sMHMjkg9WKZigqUvbRiunkcA1UwQ/exec?pattern=pattern2')

• You can retrieve the values from 'Subjects'!A1:B1000 and 'Subjects_Classes'!A1:C1000 by the query parameter.

Note:

• When you modified the Google Apps Script of Web Apps, please modify the deployment as a new version. By this, the modified script is reflected in Web Apps. Please be careful about this.

• You can see the detail of this in my report "Redeploying Web Apps without Changing URL of Web Apps for new IDE (Author: me)".