I've put together a guide to customise your own smart case for your F(x)tec Pro¹.
Facts & resources:
Soft shell cases for Huawei P20 Pro should fit your Pro¹
Fx Service: Smart Case app for Pro¹
Protective Case for Pro¹ mega thread
Cases and shells for Pro¹
Moderator: please don't merge that in the 800+ posts long topic about cases.