OP you cooked a meal of a thought 10/10.
Just wanted to also express my agreement and some of my additional thoughts.
There are two particular and very summarized ways of interpreting the memory plot device "Ian should recover his memories": 1. To understand that the Cardinal who 'took care of him' is, in fact, someone he should avoid and find dangerous; and 2. To witness that the soul in his body now is his First and Original life and is the lover of a man Ian was beginning to fall in love with.
To primarily see the latter is to overlook on Ian's current fragile psychological state, growing crippling depression, and lack of sense of self that has accumulated to poor foundation on building relationships.
Whereas those who understand and prioritize the former are those who see that the flashback is a significant supporting arc for Ian to rewrite the present and rewire his current relationships as the story's protagonist living amidst the intertwined lives and reincarnations.
People cannot forget that a person's behavior, personality, and overall thought processes are built from childhood environment, and the growing environment. Ian and Brian lived two very different lives. Ian can never be Brian, nor can Brian ever understand or live what Ian has lived through since childhood. Ian, now, can never replicate his original soul's life for he has a unique environment and sequence of events in his life that made him the way he is now.
Readers can love the flashback all they want, and how they want. If they find the flashback as something so endearing they begin to love Brian more or whatsoever, or if they see more chemistry with Sol and Brian and whatsoever. Or, better, they love the flashback as a supporting arc instead of a separate series.
But at the end of the day, a story is made with a primary protagonist who must be the center of the storyline, the spotlight of the supporting characters, and the core accumulation of character arcs. Ian, the protagonist, is the one connecting every single character in this story. This is Ian's story of how he lives the Present Timeline, how he should have his eyes opened to the fact that his so-called savior is his tormentor. Whether Ian does end up falling in love with Sol again is secondary at this point.
Considering how the story sequence went, the narration almost makes it look like Sol is looking for Brian's reincarnation, and that is something Ian should not stomach first when he's battling with how to and when he can detach himself from the abuse and isolation he's lived all his life in this present timeline.
“I prefer Brian more than Ian” mf they’re the same person the reason why Ian felt so different from Brian is because he grew up in a fucking corrupted country, was imprinted by Lorkan and was isolated by everyone. If Sol found Ian first then he could have grown up like Brian but unfortunately Lorkan found him first.
Ian may seem annoying to others after seeing the entire past now but I can’t believe people forget what was Ian’s conflicting feelings in the first place. Ian knowing he’s Brian’s reincarnation first before recovering his memories is a bad move as said by Sol because it would look like he prefer Ian’s past life more than his present self that is full of flaws. Love is something that you have to accept all of your lover’s flaws, if you can’t accept their flaws then you don’t deserve them.
I also vote on Ian should remember his life as Brian because the person who he consider his savior is the one who killed him and plan to isolate him AGAIN. But at the same time, I want him to not forget the life he lived as Ian which people want him to. Don’t brush off people’s pain as if it’s nothing that serious. Ian lived his entire life pleasing and keeping everyone’s expectations of him because they see him as an anomaly for having magic, for people to tell him to forget his mental pain and the discrimination is a fuckass move.