New user here. Glad to meet you all.
There is one problem under Windows 11 that I am having and maybe others here too but haven't noticed it.
The NEW context menu (Right Click on the Desktop) I believe uses the new Notepad app under Text Document. W11's main context menu is not your run of the mill menu anymore it appears. It seems to be handled differently than prior Windows versions.
Anyways, I was able to replace Notepad with Notepad++ under the selection Text Document. How I did it was just luck I think. If I uninstall the Notepad app as suggested then notepad gets directed to Notepad++ like it used to. However there is no longer a Text Document entry under NEW on the desktop or anywhere else NEW appears. So you can't create an empty text file. I haven't found a way to get it back because it isn't a 'normal' menu anymore (I think). I had to restore from a disk image backup. I think some menus might be in an app package now.
I think the Dev needs to research how some of the context menus work under W11 and take appropriate action.

Hi, I managed to make this work by replacing the actual notepad.exe file (obviously, back up the original), with any normal executable (a C++ "hello world" is enough).
To do so, the permissions of the notepad.exe file must be altered: the file owner is set by default to TrustedInstaller, but can be changed to your user (or the admins group) and then you can enable the "Full control" permissions to be able to overwrite it.
It needs to be replaced in c:\Windows, c:\Windows\system32 and c:\Windows\SysWOW64.
After uninstalling and installing again, Notepad Replacer now works as before.