First of all, welcome!
You've made a good start familiarizing yourself with the resources available.
As for documents, yes, their all multiple sources. The documents from obtained from the DeTomaso factory at some time so they are out there but not easily available and not cheap. You can get a Marti report for information about the car if it was in the US.
There's very little in the Prova registry. Only the administrator can grant you access. Its been difficult to reach Chuck (the admin) for a while now. There are only a few pictures from 9/2020 with the car on a trailer. The only thing of note is that it was one of 3 cars with an experimental paint color (emberglow - a copper-ish color) that changed with the light. Its interesting that he notes the car as "destroyed".
Roland Jaeckel is the primary source of parts in Europe. I haven't seen chrome bumpers for sale in a while. It looks like the damage on yours is repairable. I'd do that if I were you. They need to be re-plated anyway,