Allah does not give a person what he did not work for (on the Day of Judgement). For example, he will not simply give a murderer Paradise 'out of the grace of God'. No, sins require repentance and/or punishment (depending on the sin).
But, Allah does increase or bless a person's good deeds:
Every good deed of the son of Adam will be multiplied manifold. A good deed will be multiplied ten times up to as many as seven hundred times, or as much as Allah wills. (Sunan Ibn-Majah)
“Whosoever intended to perform a good deed, but did not do it, then Allah writes it down with Himself as a complete good deed. And if he intended to perform it and then did perform it, then Allah writes it down with Himself as from ten good deeds up to seven hundred times, up to many times multiplied. And if he intended to perform an evil deed, but did not do it, then Allah writes it down with Himself as a complete good deed. And if he intended it [i.e., the evil deed] and then performed it, then Allah writes it down as one evil deed.” (Muttafaq Alaih)
As you can see, Allah will multiply and reward a person's good deed much beyond their actual worth. But bad deeds are only recorded exactly as they are worth. This is out of Allah's grace.
Allah, the Exalted, has said: 'O son of adam, I forgive you as long as you pray to Me and hope for My forgiveness, whatever sins you have committed. O son of 'Adam, I do not care if your sins reach the height of the heaven, then you ask for my forgiveness, I would forgive you. O son of 'Adam, if you come to Me with an earth load of sins, and meet Me associating nothing to Me, I would match it with an earthload of forgiveness. (Al-Tirmidhi)
Allah is full of grace. But His grace is not giving for what you didn't do. But rather His grace is that He gives much more than you deserve for what you did do.
So, the five pillars of Islam are the minimum that must be done. They are by no means the highest that should be done. And they don't even come close to justifying forgiveness:
The Prophet (ﷺ) said, "Do good deeds properly, sincerely and moderately, and receive good news because one's good deeds will not make him enter Paradise." They asked, "Even you, O Allah's Messenger (ﷺ)?" He said, "Even I, unless and until Allah bestows His Grace and Mercy on me."
As you can see, our deeds are not good enough to get us to Pardise. We only enter it throught Grace of Allah, but our deeds are the minimum.
This is a good hadith to end on:
Messenger of Allah (ﷺ) said, "If a believer had full knowledge of the chastisement of Allah, none would hope for Jannah; and were a disbiliever to know the Grace Allah has, none would despair of Jannah". (Muslim)
As you can see, if people knew the justice of Allah none would hope for Jannah because the know they would never deserve it, but if they know of the Mercy of Allah none would lose hope for Jannah because they would know the immense grace and mercy of Allah.
In conclusion, our deeds don't justify our reward. All reward given is due to the Grace of Allah. But our deeds (five pillars are the minimum) are to show our sincerity and goodness for which Allah through His Grace will reward much beyond what was due from those deeds alone.