Cannot move to mysql

Nextcloud version (eg, 12.0.2): 16.0
Operating system and version (eg, Ubuntu 17.04): openSUSE Tumbleweed
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.3.8
PHP version (eg, 7.1): PHP 7.3.4

The issue you are facing:
I cannot move to my Mysql database:

feuerstern:/srv/www/nextcloud # sudo -u wwwrun php occ db:convert-type --all-apps mysql cloud localhost karatekcloud --password="mypassword"
The current PHP memory limit is below the recommended value of 512MB.
Creating schema in new database
The following tables will not be converted:
oc_dashboard_events
oc_dashboard_settings
oc_ocsms_config
oc_ocsms_conversation_read_states
oc_ocsms_sendmessage_queue
oc_ocsms_smsdatas
oc_ocsms_user_datas
oc_registration
oc_richdocuments_assets
oc_richdocuments_direct
oc_richdocuments_member
oc_richdocuments_wopi
oc_social_cache_actors
oc_social_cache_documents
oc_social_request_queue
oc_social_server_actors
oc_social_server_follows
oc_social_server_notes
oc_talk_guests
oc_talk_participants
oc_talk_rooms
oc_talk_signaling
oc_twofactor_yubikey
oc_weather_city
oc_weather_config
oc_xray_log
oc_xray_requests
Continue with the conversion (y/n)? [n] y
oc_accounts
 4/4 [============================] 100%oc_activity
chunked query, 5 chunks
 2000/4033 [=============>--------------]  49%
In AbstractMySQLDriver.php line 125:
                                                                                                                                                                                                                                 
  An exception occurred while executing 'INSERT INTO `oc_activity` (`activity_id`, `timestamp`, `priority`, `type`, `user`, `affecteduser`, `app`, `subject`, `subjectparams`, `message`, `messageparams`, `file`, `link`, `obj  
  ect_type`, `object_id`) VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)' with params ["2016", "1554904303", "30", "file_created", "jens", "jens", "files", "created_self", "[{\"29036\":\"\\\/Videos\\\/Spieler kontrolli  
  eren mit Metadaten! \\ud83d\\ude06\\ud83d\\ude30 _ _commandspy Plugin programmieren! & SourceCode-E7Y88bYfx6A.mp4\"}]", "", "[]", "\/Videos\/Spieler kontrollieren mit Metadaten! \ud83d\ude06\ud83d\ude30 _ _commandspy Plug  
  in programmieren! & SourceCode-E7Y88bYfx6A.mp4", "http:\/\/feuercloud.scandic.priv\/index.php\/apps\/files\/?dir=\/Videos", "files", "29036"]:                                                                                 
                                                                                                                                                                                                                                 
  SQLSTATE[22007]: Invalid datetime format: 1366 Incorrect string value: '\xF0\x9F\x98\x86\xF0\x9F...' for column `karatekcloud`.`oc_activity`.`file` at row 1                                                                   
                                                                                                                                                                                                                                 

In PDOStatement.php line 143:
                                                                                                                                                                
  SQLSTATE[22007]: Invalid datetime format: 1366 Incorrect string value: '\xF0\x9F\x98\x86\xF0\x9F...' for column `karatekcloud`.`oc_activity`.`file` at row 1  
                                                                                                                                                                

In PDOStatement.php line 141:
                                                                                                                                                                
  SQLSTATE[22007]: Invalid datetime format: 1366 Incorrect string value: '\xF0\x9F\x98\x86\xF0\x9F...' for column `karatekcloud`.`oc_activity`.`file` at row 1  
                                                                                                                                                                

db:convert-type [--port PORT] [--password PASSWORD] [--clear-schema] [--all-apps] [--chunk-size CHUNK-SIZE] [--] <type> <username> <hostname> <database>

Is this the first time you’ve seen this error? (Y/N): Yes

The output of your Nextcloud log in Admin > Logging:

It is too big, I can not paste it.

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php
$CONFIG = array (
  'instanceid' => '...',
  'passwordsalt' => '...',
  'secret' => '...',
  'trusted_domains' => 
  array (
    0 => 'feuercloud.scandic.priv',
  ),
  'datadirectory' => '/srv/www/nextcloud/data',
  'dbtype' => 'sqlite3',
  'version' => '16.0.0.9',
  'overwrite.cli.url' => 'http://feuercloud.scandic.priv',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost:54321',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'installed' => true,
  'proxy' => '172.16.0.80:3128',
  'mail_domain' => 'expamle.com',
  'mail_from_address' => 'me',
  'mail_smtpmode' => 'smtp',
  'mail_smtpsecure' => 'ssl',
  'mail_sendmailmode' => 'smtp',
  'mail_smtphost' => 'smtp.strato.de',
  'mail_smtpport' => '465',
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 0,
  'updater.secret' => '$2y$10$iKimF5ihhQ9ms3z1FoH7tOCk06MeQEPZTrBQQbJuYKTjRAU3xEjDC',
);

The output of your Apache/nginx/system log in /var/log/____: