conflict with the classic editor

We have the 5.1 version of wordpress. We have the latest of yoast premium. We are almost 4 months without the yoast premium plugin because of the conflict with the classic editor. Specifically, in the line below, function select does not exist and therefore does not return anything . That means’white page’
var first_modified;
wp.data.subscribe(() => {
// runs with each change in state
const post = wp.data.select(“core/editor”).getCurrentPost();
Our theme is jannah 3.2.0.
Please respond if you can fix he issue.