Please go through this post first.
Third Party Model Import Fatal error: Unknown device type: a - QSPICE - Qorvo Tech Forum
Major problem is that LTspice model may consist of A-device (e.g. LTC6090) which is not support in Qspice (but possibly can replace with Qspice Ã-Device and ¥-Device). But it is a tedious process. I will have a look into this part and see anything I can do when I have time.