[AI file to Affinity Designer file error error]

A major disappointment in trying to switch from Adobe Illustrator is the fact I can not open any of my Illustrator .ai files.  My files have several layers to them along with effects on some of the layers.  If I can't open these .ai files in Designer and have the ability to make changes to them means I will have to continue working in Illustrator.  The idea was to retire Illustrator, but if I have to go back and save files in Illustrator with PDF capability then it means I have to keep Illustrator.  And opening PDF compatible files in Designer doesn't bring over any effects I might have applied in Illustrator, such as drop shadows, etc.  Without being able to open the files I might just as well continue working in Illustrator.  This is something Affinity needs to correct.