Need to move Indesign 2015 off old Mac to new one

Afternoon all

I have got a copy of Indesign CC2015 with a specific HP plugin that runs on it that I can't update to a newer copy of due to the high cost. Note it isn't a hooky copy of something, its a genuine software we bought years ago and still use every week; its just hellishly expensive (000s) to get the latest version from HP and we can't do that in the current financial climate.

It runs perfectly OK on my 2017 imac which is running Monterey (having started off as Mojave and been upgraded via Software Update through Catalina and then to Monterey).

Unfortunately, the imac it is on is having some issues and needs to have a complete wipe and start afresh. BUT, you cannot download an installer for Indesign 2015 even though I have a current Creative Cloud subscription and copies of all the other 2022 CC apps running alongside it, the Older Versions option only goes back to v15 (I need 11.04).

So, how do I get the Indesign 2015 app that is running on the current mac that is wobbling, over to the same imac once it has been fixed and clean installed, which is happening shortly?

I don't want to restore from a full Time Machine really as it has lots of clutter from being upgraded so many times and I want to do a completey fresh install to make it as clean as possible and you can't selective just bring over apps as i understand it?

Does anyone know how I can get this accomplished? Is there a definitive method of doing this by just copying critical files and associated Preferences etc?

Any help really appreciated. Cheers for looking.
Nev