The Prophet (saw) had a camel called al Adbaa and he would race people and beat them. Once, a Bedouin came with a young camel below six years of age and beat the Prophet (saw). The Sahaaba were affected. The Prophet (saw) said, it’s Allah’s Law that everything which rises in the dunya, Allah will bring it down.
When you reach your peak, you’re going to go downhill, physically or otherwise.
He (saw) mentioned anything of the dunya will go down but he didn’t say the Aakhirah! So, anything done for the Aakhirah will not go down, rather it goes up, such as a project or something left behind as a legacy!
When something is done for Allah, with sincerity, knowledge and emaan, it’ll increase.