Deindexing and removing OLD Blogpost in Sitemap

Good day! What do you do if a magazine publishing site has old posts (2008-2019), not getting traffic now because they are old, and don't have backlinks. Do we need to deindex them to save crawl budget and maybe removing them in sitemap also? Because the site has many pages and I have run the website in Screaming Frog for 12hrs it is still not finished. And how do you consider it as old as it can be deindexed?