Via the WordPress customizer at Appearance > Customize > Blog > Archives & Entries you can easily alter the default text for your blog entries readmore button. If you want to conditionally alter the text this can also be done via a function in your child theme.
Important
This setting is specifically for the default blog entry design only. For full control over your blog archives it’s recommended to create a dynamic template this will way you can completely design your archives exactly how you want rather than relying on the default design and pre-set options. You may also consider creating a custom card to use for your entries.
