My two gripes here are how did the AI/Nanom know that he had to use mental imaging to manifest the fireballs? I guess one can conclude that from the narrative, Alan and Cleria may have talked in greater details about how magic was used, but that's not how it was presented in the manga. In the manga, the AI/Nanom simply analyzed her and then explained to him how to use magic and she was even surprised by his prowess in using magic. She gave no detailed explanations about it from what we saw.
My second gripe is that now that he uses magic, and uses it to such a high level with AI/Nanom helping him, that's going to minimize his need for his technology. I suspect now this was the authors intent all along, the whole man from space thing was only the gimmick used to prop up the early chapters and now we're going to cruise into typical Isekai tropes, not that I'm complaining entirely. I just hoped he would be using a combination of his tech (guns, high-tech armor, whatever) and his experience from playing VR games (sword fighting) to move through the story and maybe once Ms. A.I. Conrad got online, she'd be able to help out a bit more from orbit.
Him using magic isn't a killer for me. It's fine and to be expected once the fantasy world trope was used, but guess I'm just a little disappointed that the author didn't go the path of other modern soldiers in fantasy game world plots where the modern/future soldier can't use magic and has to focus on using their tech.