The best editor I’ve found is Qoppa PDF Studio. Although not free it is cross-platform (written in Java) and their licenses are perpetual. They do have a free v

The best editor I’ve found is Qoppa PDF Studio. Although not free it is cross-platform (written in Java) and their licenses are perpetual. They do have a free viewer app which can fill interactive forms and this works on Windows, Mac and Linux: Qoppa PDF Studio Viewer.