You know, I would like it if it turns out that the MC has always been Takeru all along. Yamato was his previous life that got isekai then Takeru is his current reincarnation. The coma awakened his past life memory but also caused actual real amnesia.
I would prefer thing to actually be like that since the idea of being in another body really makes me uncomfortable.
Thats what I've been thinking for a while, Yamato being Takeru makes a bit of sense as Yamato hasn't really changed how he acts to be Takeru and when the exorcist looked at Takeru's souls she only found Yamato...The DAMAGED soul of Yamato meaning it could be possible that the damaged soul of Yamato simply doesn't remember his life as Takeru.
With Takeru now being able to use magic and such could literally be because of Yamato's damaged souls, we saw the split soul of Yamato's during the exorcism so maybe Takeru only had half his soul and now that Yamato has awoken (due to Takeru's self deletion) Takeru now with the memory's of Yamato and the ability to use magic.
Tldr:
Takeru= reincarnation of Yamato
Yamato's damaged soul = Takeru being unable to use magic
Takeru self deletion = soul's other half finally getting connected but the trauma of it all gave him memory loss of his life of takeru but the memory's of Yamato
Soul connected to other half= magic can finally being used.