Is It Possible To Change Dates Within Site / Rss Feed / Sitemap

For reasons that people may not understand. I would ideally like to change my sitemap/rss feed and site in general to make the website look older than it is. This has some big advantages for aggregators, and although you won't fool google, you will certainly trick some of the smaller players who do human checks.

If you check a random news sitemap (smaller ones with less sophisticated layouts) they're usually managed by Yoast, Rankmath or AllinOne. Here you can scroll back through the dates and see when they first and last posted, as well as everything in between.

I wondered if there is a way to do this such as changing the date internally within your site to fool the plugin in to thinking you've been making content since 2021 for example?

A plugin like this might work, there may be better plugins but just so you get an idea.

https://wordpress.org/plugins/bulk-datetime-change/