https://www.reddit.com/r/Genshin_Impact/comments/j6wez0/psa_characters_hidden_bonus_when_ascending/
when ascending, 5-star character has 20% more bonus than 4-star character of the same type. However, traveler is considered a 4-star character in term of ascending bonus
ATK: Traveler, Fischl, Chongyun중운, Xingqiu행추, Amber
Energy recharge rate: Mona, Bennet, Kaeya, Venti
Physical damage bonus: Razor
Elemental damage bonus: Sucrose (Anemo)설탕, Ningguang (Geo)응광, Beidou (Eletro)북두, Klee (Pyro)
Elemental Mastery: Lisa, Xiangling향릉
Crit rate: Diluc
Crit damage: Keqing각청
Heal bonus: Jean, Qiqi치치
DEF: Noelle
HP: Barbara