Chibnall, being at heart a vandal and only interested in what he personally thought was cool, decided to completely destroy Time Lords again and to really try hard to not let any future showrunner be able to use them.
EDIT - I'd also add that change in context means the Doctor seems far less brave and moral. As a rebel Time Lord, the Doctor was a person rejecting a bad society and choosing to help people, no matter the cost and risk. As the Timeless Child, he's just a superior magic space god, who was never genuinely a Time Lord, who was always literally "better" than them, just a victim who got tricked and used, and the Doctor's bravery and moral stand seem far less impressive. It's a far more simplistic conception that has far less relevance and relatability, which sucks.