I think I read this in 2022. It was definitely after 2020. I believe it was fairly recent at the time. It is a Japanese black & white manga. The demographic is either Shoujo or Josei. I don't recall any characters names or appearances.
The main character is a noble or royalty of some sort, but is maligned by her family and possibly society due to a lack of magic power. For some reason I can't precisely recall, she ends up leaving her house and going to another country. I assume for one of these reasons,
- She decided to run away because she was sick of her family's treatment
- She was kicked out for her lack of magic power
- She was married off to a noble from another country in a purely political marriage.
I can't remember for certain which it is. If she was a runaway, I think she cuts her hair to be less obvious. Regardless, she leaves the country and meets a man, the male lead of the story, and they start traveling together. If he isn't already her husband, I think he was a noble pretending to be an adventurer. If so, he wasn't alone and had other male companions.
Some circumstances lead them to a spring, lake, fountain, or some other body of water. After entering or praying at the water, she suddenly awakens to her full magical power. The reasoning behind this is that there's a baptism-like ceremony for awakening magic powers, and she is from this other country. During her ceremony she was baptized at the wrong "incompatible" country, and this is why she always seemed to have a severe lack of magic power. I think she was either adopted and never informed of this, or she was actually the child of a mistress from this other country.
I think that was the last chapter that I read and don't know anything that happened afterwards. This was probably around chapter 5 or 6. Fairly early in the story, but definitely not in the first chapter. The exile would be in the first chapter.
I don't remember any isekai or reincarnation elements, but I can't rule them out.