My colleague lkrupp is referring to the Recent Items menu, for which there is a clear option and the ability to specify the number of items shown. That is not relevant to your question about the Recents folder.
The Recents folder is a Smart Folder created and maintained by macOS. It's not a folder in the traditional sense, rather it's a live view of search results. You cannot manage the contents of that folder, and if you remove files from it you are removing the original files.
What you can do is hide that folder in Finder menu > Settings > Sidebar tab, untick the box. However, you cannot remove it from the Go menu in Finder.
Only Apple could change that (though in this case, it seems unlikely): Feedback - macOS - Apple
Strategically, if your goal is to keep files out of the Recents folder, I have noticed that files on other disks are not included (because they are not indexed by Spotlight). This also applies to disk images that are stored on the internal drive. For example, I keep my financial information on an encrypted disk image stored on my internal drive, and when I open an old tax return or a scanned passport image, those files do not show up in the Recents folder.
Create a disk image using Disk Utility on Mac - Apple Support
That won’t help clear files currently in the Recents folder, though.