What is the correct understanding of tribulation ( ابتلاء) from an Islamic perspective, such that it aligns with God's absolute knowledge and does not contradict His perfection, Subhanahu wa Ta'ala?

Tribulation serves to expiate sins and erase misdeeds, and to elevate ranks and increase good deeds. A believer may be punished through it for some sins, and it may be for the purification of believers and distinguishing them from hypocrites, and to reveal one's state of contentment or displeasure with Allah's decree.