Android Studio: Unable to determine activity name

I created an app in Android Studio (2022.3.1) that just contains a webview and handles urls.
It worked until I added deep links via intent. Can someone tell me, whats wrong with that?

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    >
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.FullscreenDark"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:theme="@style/Theme.FullscreenDark">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:host="@string/app_host" />
                <data android:scheme="http" />
                <data android:scheme="https" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MainActivity.kt:

package com.app.myapp

import android.annotation.SuppressLint
import android.os.Bundle
import android.webkit.WebSettings
import android.webkit.WebView
import android.webkit.WebViewClient
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

    private lateinit var webView: WebView

    @SuppressLint("SetJavaScriptEnabled")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val host = getString(R.string.app_host)

        webView = findViewById(R.id.webview)
        val webSettings: WebSettings = webView.settings

        // Configure settings
        webSettings.javaScriptEnabled = true // Enable JavaScript
        webView.webViewClient = MyWebViewClient()
//        webView.webViewClient = WebViewClient()

        // Check for deep link
        val intentData = intent.data
        if (intentData != null) {
            val deepLink = intentData.toString()
            webView.loadUrl(deepLink)
        } else {
            // Load your default URL
            webView.loadUrl("https://$host")
        }
    }

    @Deprecated("Deprecated in Java")
    override fun onBackPressed() {
        if (webView.canGoBack()) {
            webView.goBack()
        } else {
            super.onBackPressedDispatcher.onBackPressed()
        }
    }

    private inner class MyWebViewClient : WebViewClient() {
        @Deprecated("Deprecated in Java")
        override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
            val host = getString(R.string.app_host)

            // Load URLs from the same domain within the WebView
            if (url != null && url.startsWith("https://$host")) {
                view?.loadUrl(url)
                return true
            }
            // Load all other URLs in the default browser
            return false
        }
    }
}

I tried setting it up again from scratch several times and looked up other examples.

When I run it, I get this error everytime:
Unable to determine activity name

Update:
Changed AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    >
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.FullscreenDark"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:theme="@style/Theme.FullscreenDark">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />

                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:host="@string/app_host" />
                <data android:scheme="http" />
                <data android:scheme="https" />
            </intent-filter>
        </activity>
    </application>
</manifest>

New error message: Activity class {com.app.myapp/com.app.myapp.MainActivity} does not exist