…and there you are - you gotta work for it. I opened a discussion about this work and the way new users could be educated here.
I agree that there should be more material to help users, but on the other hand one should consider that PureOS is nothing more than a Debian subclass. There are things missing that do not adhere to the Free Sofware Foundations principles, but in general it is Debian.
For Debian there is a lot documentation around and probably there is a Linux / Debian user group near you and for sure there will be somebody willing to teach you.
Maybe this helps to find your way into the system: Look at PureOS as it would be Debian, get connected with other Debian users near you and be sure that support and the users here will be open for your questions when it comes to the small differences.
The installation of e.g. the Monero GUI probably is not different inbetween PureOS and Debian. The general use of the LibremKey (which is a variant of the nitrokey) is not really bound to PureOS - the concepts and the use is very similar between other Linux distributions and PureOS. Especially the GPG/PGP features you’re asking for work exactly (as far as I used them) like described by the GPG community for any GPG usable smartcard.
There are things you can only find here in the Purism community. E.g. the use of the LibremKey to validate your bios and boot environment at startup.
This sounds really like one of those problems any Debian administrator could help you to solve. If you prefer to have someone over you’ll probably find people in your area.