First, a belated welcome to Android Forums, 88keyplayer!

I rarely visit this board any more, so I didn't see your post until now.
Will Brave create these .org.chromium.Chromium files? I have 2 listed in my phone and have never seen them before today after using an Android File explorer app from Play.
I'm guessing that it's the file manager, not the browser, causing this.
I have several reasons, including the fact that you've never seen them before installing the FM app.
After reading
this thread about a Linux program, Zulip Electron, creating large numbers of .org.chromium.Chromium.xxxxxx files on computers, I deduced that an Android app could do the same on an Android [Linux] device.
From that same thread I found that Opera browsers create those files, too. But, again, since you've been using your browser, Brave, before ever seeing these files, I don't think they're related.
On Linux computers, in the first person's case, they're stored in /tmp, which is a directory that's usually cleaned up by the system, including emptying it following its [very rare!] reboots.
If you can tell us where your files are located, that will help figure out what, if anything, to do about them.