Hello there,
Wonder is a block based theme (the new WordPress theme technology), so you can’t manage your typography like you used in the past via the customizer.
You have to use the “Site Editor”.
You can change the typography globally or elements by elements.
Here a couple of reference about the WordPress block theme management and editing:
– https://www.ads-software.com/documentation/article/typography-settings-overview/
– https://www.ads-software.com/documentation/article/site-editor/
– https://www.ads-software.com/documentation/article/styles-overview/
The last link is what you need the most.
I hope you will appreciate this little help and hint on where to look for the typography options on a block based theme.