I mainly use PowerPoint for science talks. I'd like to use Impress, but it's very buggy. It may be caused by importing PPT(X) files, but parts of slides become

I mainly use PowerPoint for science talks. I'd like to use Impress, but it's very buggy. It may be caused by importing PPT(X) files, but parts of slides become randomly uneditable and styles randomly don't work. The PPTX import often randomly breaks.