Isn't it already what the PortableApps release 2 do?
Not really.
I'm not an expert on this, but from what I've gathered, they have a specific custom format for their packages that dictates both the file and directory layout as well as the operating behaviour of portable apps. Therefore, (AFAIK) they create new launchers to adapt the behaviour of each app to their format.
What I am trying to do here is to only use the functionalities already available in Joplin and avoid any other dependency. This should allow a more stable and future-proof solution.
Furthermore, if this experiment is successful, I hope it could serve as a foundation for a proper Portable version of Joplin (see, for instance, Joplin Portable should have everything in the same place).
Moreover, by using this approach you are completely independent from PortableApps.com Platform and releases/updates.
As you have noticed in this post, they might not be very active or not have the resources to support all apps; for instance, at the moment for Joplin their "Date Updated" is "2024-05-23" and it is still v2 (even if we know that v3 has been released long time ago).
In addition, as you pointed out in this post, there is no interest in maintaining another different package/platform; that is why I am trying to only use the functionalities already available in Joplin.
However, please let me know if I am overlooking anything.