Ok, so I found it, downloaded it, did a quick test and it seems to work on Win11.
So the file was flagged as a virus, hence no direct links and discontinued, understood. I hope I can copy Jon's link and version here for future reference. If not, I'll be glad to comply.
I'm looking at adding it to SciTEUSer.properties as referenced on that post by Jos and fidgetting with https://www.autoitscript.com/autoit3/scite/docs/SciTE4AutoIt3/SciTE4AutoIt3-user-options-file.html I'll edit If I'm successful.
EDIT: Yes! So SciTE opens SciTEUSer.properties from Current user AppData (C:\Users\You\AppData\Local\AutoIt v3\SciTE\SciTEUser.properties), not the SciTEUSer.properties in the app folder "C:\Program Files (x86)\AutoIt3\SciTE\SciTEUser.properties". You can open it from the options menu and append to the end of it:
command.40.$(au3)="C:\Program Files (x86)\AutoIt3\Au3Record\Au3Record.exe"
command.name.40.$(au3)=Au3Record.exe
command.shortcut.40.*.au3=Ctrl+Alt+Shift+Z
command.subsystem.40.$(au3)=2
command.save.before.40.$(au3)=2
command.quiet.40.$(au3)=1
The number can be anything, I saw no others in my file so I left the example.