Theme Horse

Actually for Grid Layout as per design perspective, excerpt is control for maximum of 126 character also the the excerpt option won’t work if you set the texts on excerpt field on page/post editor. The excerpt will show auto from the content text and can control from the excerpt option from customizer.
If you want to increase the character limit from 126 then please go to “Theme Directory > inc > structure > content-extension.php’ on line no: 145, you can change the number from 126 to any.
It will be better to create a child theme first before customizing the Theme code so that your customized code won’t get lot when updating the Theme to a newer Version in future.

Thanks