Ability is a very crucial factor in the recent period. Everyone judges people by their ability and their strength. To know about this in detail, check out this article.

I’m doing my hardest: By using this expression, one can tell they have given a task their all. They may have expended all of their physical and mental resources to finish it, as suggested by the phrase.

For illustration, say, “I gave the marathon my all during training, and I’m happy to report that I made it through.”

To the best: Given the restrictions or limitations they were working within, this expression implies that the person has carried out a task as effectively as possible.

I studied as much as I could in the time I had for the exam, but I was unable to cover everything.

As good as I could: This expression denotes that the speaker made the best effort possible given the information, abilities, and resources at hand. It means that they might have faced obstacles or limiting factors that kept them from accomplishing more.
Example: “I painted the picture using the paints and brushes I had available as best as I could.”

To the best of my knowledge: This expression denotes that the speaker has, to the best of their ability and based on the information at hand, presented accurate and trustworthy information.
Example: “As far as I’m aware, the business has never run into any legal troubles.”

Everything that I have is: This expression denotes that a person has given a task their whole attention in order to produce the best results possible.
As an illustration, say, “I gave the project everything I had, and I’m certain that we’ll achieve amazing outcomes.”

Finally, there are a variety of ways to convey that something has been completed to the best of one’s ability. The term chosen will depend on the situation and the amount of stress being conveyed.