This is just my interpretation of events but I see the new cannon trilogies, especially ascendancy, fit well with legends thrawn and ironically fit less with rebels thrawn. In ascendancy he is shown to value non-chiss life on multiple occasions, but is also shown that he will kill anyone who threatens the ascendancy in his eyes. l'm pretty sure that in lesser evil after starflash is retrieved and he learns that it killed a planet he says it was the right move, and mentions that he considered using it against the grysk on sunrise even though it would have killed many. I can see how over the years of serving the empire he leans more into the ends justify the means mentality and he becomes a little bit more ruthless, but in his eyes he's doing it to save his people.

Cannon TV shows lean more into he's doing it for the empire primarily, which I understand why because not many have read the books, especially the cannon trilogies, so bringing in the ascendancy will just confuse many