@vikou1008
Is it possible to replace the “read more” link by a customized button?
In any theme, you can add your own wording to the default Read More link like this:
<!--more Keep on reading!-->
You can also style the resulting button by targetting the more-link
class on the element it outputs with some CSS.
And also, is it possible to get the “read more” link to scroll at the beginning of the post (at the level of the post category or title) instead of the “more” anchor?
That’s Core WordPress behaviour. There’s a function here you might want to try in a child theme or functionality plugin:
https://digwp.com/2010/01/wordpress-more-tag-tricks/
It’s quite an old tutorial though – be careful and test locally first or on a test site if possible. Don’t edit the original theme files – be sure to use only a child theme or functionality plugin.