While there’s no duplicate content penalty (official Google statement source), having a significant portion of the website flagged by Google as duplicate content (i.e. 50%+), can lower the quality of the entire website. This will negatively affect the ability of the quality pages to rank where they would deserve. You need to properly consolidate your content, to avoid wasting crawl budget on duplicate content. Official recommendation on how to handle duplicate content can be found here.

According to an official Google statement, duplicate content may hinder the ability of correct pages ranking in SERPs:

“PageRank and similar information found via incoming links can get diffused across pages we aren’t currently recognizing as duplicates, potentially making your preferred version of the page rank lower in Google” source