Was just mentioning Toad Lily as an easy example (i don't have her either T^T), but 452 Speed shouldn't be too bad until you can level up some faster unit.
However, do try to max your 5*'s affection and level/evolve her before other lower-rarity Slice-type knights - the difference in stats, affection bonus, battle skills, and abilities with lower-rarity girls is usually pretty huge, even if they can use less Equip. Besides, even if i don't know what 5* you have, both Slice 5* are really good units~