Update of Libraries and Processes from Legacy to Windows - Build Pipeline

Sorry, I am very junior in UiPath programming but, how can we proceed then? I have create a new xaml within an old library that was use in a projects in the Legacy scheme. I have done the same: modify the xaml in the library and try to publish it so that I could use this xaml as an activity in my Legacy projects that used it. However, when I try to publish it, the system is throwing tones of validation errors of all projects I have, and concluding that I cannot publish the library project because I have all these validation errors. Can anyone help to find a way to get my library with my new xaml accesible for my old projects in Legacy system? I am about to loose many months of work!!!