Effort moves odds. A long shot you work on every day isn’t that long anymore.

A long shot is only long under current conditions, and daily work changes the conditions. Each session moves you a small amount and the odds quietly recalculate in the background while you are not thinking about them, which is why somebody three years into a thing looks lucky to everyone who arrived late.

Pick the thing you have written off as unrealistic and give it a small daily slot. Twenty minutes counts. Reassess after three months rather than after three days, because three months is roughly when the numbers start to have actually moved.