How to update InDesign 18.0 to 18.3/4/5

So I have some customers that are still on InDesign 18.3 and 18.5 and they cannot update to a later version because they are using third-party software that is locked to these versions. After purchasing some new hardware, they are unable to download or install InDesign 18/2023 via the CC app. I reached out to Adobe support, but all they would give me is a link for an 18.0 installer. The installer works, but there is no longer any way for the CC app to update it to 18.3/4/5. I have asked them repeatedly and the same answer every time-this is the only installer we have OR update to 2024 or 2025 which is not an option. The only thing that has sorta worked is copying the InDesign app itself from a working machine and copying over the 18.0 version that got installed with the installer. This is a less than ideal solution-anyone have any ideas or access to 18.3/4/5 updates, directly?