Hi @Lina Arras
Per my test, I will be unable to reporduce your issue. But I will be unable to get the theme in Change the look if I upload a
fontscheme.spfont file with error content. The orange theme will disappear in theme.
So I guess if there is some error in your fontscheme.spfont file and will cause the font doesn't show in try out mode. Please refer to the document
Color palettes and fonts in SharePoint
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