Alright so I have a question regarding blood status. If you have a grandparent who is a wizard, but they had a kid with a muggle. The kid didn't have any magic and their partner is also a muggle, and then they had you, who has this distant relative with magic, does it count as Muggleborn?

No one knew about magic since the grandparent didn't tell and everyone else is a muggle. Would you be a Muggle-born or would you be Half-blood?

Half-blood because you are still descended from a magical and have the line in your blood, even though you may believe you are a muggle since it was hidden. Hope this helps.
Warm regards,
Edward Edwards
@Sini Íbarez Sorní

If one of your character's grandparents is magical, they would still be considered halfblood. If it is the great-grandparents, they would be muggleborn.