Attempt to add 1 TMS component to my Delphi set up has broken everything

I am using Delphi 12.1.

I did a full install of some TMS components in April. My IDE was fully funtional.

Today, I realised I needed an "Hour picker" for a project, and saw that this was present in the TMS FNC UI Pack (which I did not have installed).

I opened the TMS Subscription manager and downloaded the TMS FNC UI Pack, this said it needed the TMS FNC Core to be installed.

I downloaded and installed TMS FNC Core. This failed, reporting "Multiple complex errors", when I run Delphi now I get a large number of errors, and I think I can no longer access any component that references FNC Core.

Is there any instruction about how to un-do this? Steps I should take to restore my IDE to a working state?
Do I need to uninstall and reinstall multiple TMS components?

I was foolish enough not to save my set up prior to this action, so I now cannot build any projects that reference FNC Core components.

In future, when I install or reinstall a single TMS component, is it advisable to uninstall multiple components first?

Please send the installer generated log file via direct email (not in this support center as it contains possibly sensitive information)
With this log file we can inspect what is possibly wrong on your machine.