Add Custom Fonts

I am trying to add custom fonts (part of Adobe Fonts enqueued with your https://wordpress.org/plugins/custom-typekit-fonts/ plugin) website to the Font Family selector in the typography options (e.g available in the Headline Spectra Gutenberg block).

I am using the following code to add my Adobe Fonts (since they are not automatically added to Spectra) and it works. Except, I cannot find a way to define the fallback fonts as ‘value’ and ‘label’ are ignored. Spectra just used the array key as the font label and value.

add_filter('spectra_system_fonts', function($fonts) {
    $fonts['Meno-Display-Condensed'] = (object) [
        'value' => "Meno-Display-Condensed",
        'label' => "Meno-Display-Condensed",
        'weight' => ["Default","100","200","300","400","500","600","700","800","900"],
        'google' => !1
        ];
	$fonts['Adlery-Pro'] = (object) [
		'value' => ["Adlery-Pro,adlery-pro,sans-serif"],
		'label' => ["Adlery-Pro"],
		'weight' => ["Default","100","200","300","400","500","600","700","800"],
		'google' => !1
	];

    $fonts['Tablet-Gothic-Condensed'] = (object) [
		'value' => "Tablet-Gothic-Condensed,tablet-gothic-condensed,sans-serif",
		'label' => "Tablet-Gothic-Condensed",
		'weight' => ["Default","100","200","300","400","500","600","700","800","900"],
		'google' => !1
	];
  return $fonts;
});

How can I define the fallback font or what gets added to the font-family css attribute?
Thank you for your help!