older versions of indesign

The question is what exactly did you buy and from whom? If you have a genuine subscription then you should have checked the system requirements before making the purchase. Adobe provides installer only for the current and one prior version and both these version would at the least need 8 GB of RAM. If you can't upgrade the computer due to any reason then the best possible way out is to contact Adobe support and try to get it cancelled.

If it is not a subscription then I suppose you got scammed or at the least sold an obsolete version of the software.

-Manan

If you have a valid Serial Number - for CS5 / CS5.5 and probably CS6 - you could register it on your account and you should be able to download installer.

I can confirm, that CS5 and CS5.5 IS still available for download for Windows - CS6 probably would be as well, but I forgot to register it and now I don't have the box / paperwork at hand to register it.

Not sure how it works / worked on Macs - but on Windows, you could ask someone to give you installation DVD / ISO image for before-CC-versions.

And it looks like I still have 20GB DVD ISO with "Adobe Creative Cloud Collection 2020-2021" - "Adobe InDesign 2021 v16.0.0.77".