until, up to, as far as, to the extent
迄 centers on reaching a limit or endpoint: until a certain time, up to a place, as far as something extends, or to the extent of a condition.
迄 combines the movement radical 辶 with 乞, which likely contributes the sound. The character expresses the idea of reaching a point or limit.
The movement radical 辶 suggests going along a path, and 乞 looks like a person reaching out. Together, they show moving until you reach a destination or limit.
For キツ, imagine a kitsune (fox) walking along a path until it reaches a shrine gate: kitsune -> キツ, and the fox goes up to the gate.