iOS Share extension shows my app but does not open it after clicking on it

I have added share extension to my iOS app. Then I deleted the storyboard from share extension. My ShareViewController code is as follows

import UIKit
import Social
import CoreServices
import UniformTypeIdentifiers

class ShareViewController: UIViewController {

    private let typeText = UTType.text.identifier
    private let typeURL = UTType.url.identifier
    private let appURL = "MyExtension://"
    
    private let groupName = "group.sharingsampletwo"
    private let urlDefaultName = "incomingURL"

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        // 1
        guard let extensionItem = extensionContext?.inputItems.first as? NSExtensionItem,
            let itemProvider = extensionItem.attachments?.first else {
                self.extensionContext?.completeRequest(returningItems: nil, completionHandler: nil)
                return
        }

        if itemProvider.hasItemConformingToTypeIdentifier(typeText) {
            handleIncomingText(itemProvider: itemProvider)
        } else if itemProvider.hasItemConformingToTypeIdentifier(typeURL) {
            handleIncomingURL(itemProvider: itemProvider)
        } else {
            print("Error: No url or text found")
            self.extensionContext?.completeRequest(returningItems: nil, completionHandler: nil)
        }
    }

    private func handleIncomingText(itemProvider: NSItemProvider) {
        itemProvider.loadItem(forTypeIdentifier: typeText, options: nil) { (item, error) in
            if let error = error { print("Text-Error: \(error.localizedDescription)") }


            if let text = item as? String {
                do {// 2.1
                    let detector = try NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
                    let matches = detector.matches(
                        in: text,
                        options: [],
                        range: NSRange(location: 0, length: text.utf16.count)
                    )
                    // 2.2
                    if let firstMatch = matches.first, let range = Range(firstMatch.range, in: text) {
                        self.saveURLString(String(text[range]))
                    }
                } catch let error {
                    print("Do-Try Error: \(error.localizedDescription)")
                }
            }

            self.openMainApp()
        }
    }

    private func handleIncomingURL(itemProvider: NSItemProvider) {
        itemProvider.loadItem(forTypeIdentifier: typeURL, options: nil) { (item, error) in
            if let error = error { print("URL-Error: \(error.localizedDescription)") }

            if let url = item as? NSURL, let urlString = url.absoluteString {
                self.saveURLString(urlString)
            }

            self.openMainApp()
        }
    }

    private func saveURLString(_ urlString: String) {
        UserDefaults(suiteName: self.groupName)?.set(urlString, forKey: self.urlDefaultName)
    }

    private func openMainApp() {
        self.extensionContext?.completeRequest(returningItems: nil, completionHandler: { _ in
            guard let url = URL(string: self.appURL) else { return }
            _ = self.openURL(url)
        })
    }

    // Courtesy: https://stackoverflow.com/a/44499222/13363449 👇🏾
    // Function must be named exactly like this so a selector can be found by the compiler!
    // Anyway - it's another selector in another instance that would be "performed" instead.
    @objc private func openURL(_ url: URL) -> Bool {
        var responder: UIResponder? = self
        while responder != nil {
            if let application = responder as? UIApplication {
                return application.perform(#selector(openURL(_:)), with: url) != nil
            }
            responder = responder?.next
        }
        return false
    }
}

Then I added appgroups capability for my main app target as well as share extension

Then I edited info.plist of my share extension

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    
    <key>NSExtension</key>
    <dict>
        <key>NSExtensionAttributes</key>
        <dict>
            <key>NSExtensionActivationRule</key>
            <dict>
                <key>NSExtensionActivationSupportsText</key>
                <true/>
                <key>NSExtensionActivationSupportsWebURLWithMaxCount</key>
                <integer>1</integer>
            </dict>
        </dict>
        <key>NSExtensionPointIdentifier</key>
        <string>com.apple.share-services</string>
        <key>NSExtensionPrincipalClass</key>
        <string>Share.ShareViewController</string>
    </dict>
</dict>
</plist>

Then in my appdelegate I added following code

func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
      if let scheme = url.scheme,
        scheme.caseInsensitiveCompare("MyExtension") == .orderedSame,
        let page = url.host {
        
        var parameters: [String: String] = [:]
        URLComponents(url: url, resolvingAgainstBaseURL: false)?.queryItems?.forEach {
          parameters[$0.name] = $0.value
        }
        
        print("redirect(to: \(page), with: \(parameters))")
        for parameter in parameters where parameter.key.caseInsensitiveCompare("url") == .orderedSame {
          UserDefaults().set(parameter.value, forKey: "incomingURL")
        }
        
      }
      
      return true
      
    }

Do I need to have paid apple developer account for this? What else am I missing

You need to add a URL scheme in your project file.
Project > Info > Scroll down to URL Types > Add a new URL type.

Make sure the URL scheme you create match the one you define in your share extension (i.e. MyExtension:// in your case).

Refer the to Apple docs for URL schemes for more info.