There is a plugin that prevents Google Fonts from being loaded from the Google Server. It installs Google Fonts locally. Feel free to try it. You will find it here:
https://github.com/joomtools/plg_system_jtaldef

And here is a link to a Google Fonts Checker Tool:
https://sicher3.de/google-fonts-checker/

How can i complete disable google Fonts in Maya Template. Where can i find the Code?

- Goto Site Template Styles > Your_Template > Tab «General» > Typography Styling
- Body font > Scroll to the very top of the list
- Choose one of the fonts in the «Web Safe Fonts» section

Repeat step 2 and 3 for any other font style definition such as «(H1) Category Head Font» and so on

That is not the answer!
we have entered websafe fonts everywhere and still https://fonts.googleapis.com/css?family=oswald is reloaded.

I am not Ciaran but I suggest looking for the file templates/j51_xxx/inc/font.php
Disabling this section might resolve the issue:

$googlefonts = array_diff($googlefonts, $websafefonts); // remove websafe

$googlefonts = array_keys(array_flip($googlefonts)); // remove duplicates

$font_subset = str_replace(' ', '', $font_subset); // remove spaces

$font_weights = str_replace(' ', '', $font_weights); // remove spaces

foreach ($googlefonts as $v) { // loop

	$app->getDocument()->addStyleSheet('//http://fonts.googleapis.com/css?family=' . $v . ':' . $font_weights . '&&subset=' . $font_subset . '&display=swap');

}

this file doesnt exist

wow i found it in the index.php

<meta name="author" content=" Allerseiten - Thomas Grummt">
<meta name="copyright" content="Thomas Grummt" />
<meta name="page-topic" content="Mastavit - Herstellung und Vertrieb von pharmazeutischen Produkten">
<meta name="robots" content="index,follow">
<link rel="apple-touch-icon" href="https://www.mastavit.de/apple-touch-icon.png"/>
<jdoc:include type="head" />
<?php include ("inc/head.php";?>
<?php include ("inc/scripts.php";?>
<?php echo $this->params->get('head_custom_code'); ?>
<!--
<link href="https://fonts.googleapis.com/css?family=Oswald"; rel="stylesheet">
-->
</head>