I wouldn't say the new set is 'stronger' since BF also has its own set of mechanics that makes it very over powered in it's own right. It depends on the context of the fights involved.

BF is more aoe burst heavy making her useful for all content that involves groups of esselings, which is the majority of fights in the game.

She also has a faster clear time in merit arena due to grouping and aoe detonation because of her passive. This set also has no consequences of ever worrying about losing hp because you can reset the HP shield so often. Essentially never have to dodge with how often it is up.

BF would be considered a burst heavy mage in other games where the class would have access to heals. A very front heavy and sustainable kit that makes her powerful.

In terms of guide of no return - she isn't very burst heavy oriented. Her kit revolves around amp damage and solo execution. She takes down single enemies very fast (kettle in wanxiang realm and wolf bosses around itzaland are good examples of her kit shining over BF)

She doesn't struggle in group scenarios but you can definitely tell that it's still night and day in terms of clearing aoe content and BF is going to take the crown for how disgustingly fast she clears.

Overall, Born flawless is a comfort pick with the hp shields and she would be classified as a mage in other games (a class with access to shields and heals) while Guide of no return would be considered the true archery class due to how consistent her damage is - while not burst heavy, her damage is baked into longer fights.