The person who helped you stay steady belongs in the memory of reaching the goal.

Achievements get remembered as solo efforts because the final push is the vivid part. Steadiness, though, usually came from somewhere. Someone covered the evenings, or listened at the low point, or kept ordinary life running while you were not available to it. Leaving them out is not modesty. It simply makes the account inaccurate.

Name one person who carried part of the weight during your last long effort, and tell them exactly what they did. Specifics land where general thanks does not.