Can you please attach the project itself? It would almost certainly be sufficient for you to cut the project down to just a couple of bars, if you have worries about attaching the whole thing here.
See this sticky thread for our advice on how to most effectively ask for assistance here:
My guess is that the issues will arise from the way Dorico is choosing which instrument types to create based on the Italian names in the MusicXML file. Because MusicXML doesn’t have a direct way to define an instrument (just some information about an instrument, such as how its staves should be labeled, and what sound it should use, and almost all of this information is also optional rather than mandatory), applications have to employ heuristics to determine which instruments to create.
In theory Dorico should do this just as capably in Italian or German as it does in English, but in practice it doesn’t always work quite as well, and it can be advisable to use Change Instrument after importing your MusicXML file to be sure that each instrument really is what you expect it to be: