Self-Inflicting Hardship

Self-inflicted suffering/hardship – المشقة – is not rewarded:

Imam Bukhari narrated in his Sahih:
حَدَّثَنَا ابْنُ سَلاَمٍ، أَخْبَرَنَا الْفَزَارِيُّ، عَنْ حُمَيْدٍ الطَّوِيلِ، قَالَ حَدَّثَنِي ثَابِتٌ، عَنْ أَنَسٍ ـ رضى الله عنه ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم رَأَى شَيْخًا يُهَادَى بَيْنَ ابْنَيْهِ قَالَ ‏”‏ مَا بَالُ هَذَا ‏”‏‏.‏ قَالُوا نَذَرَ أَنْ يَمْشِيَ‏.‏ قَالَ ‏”‏ إِنَّ اللَّهَ عَنْ تَعْذِيبِ هَذَا نَفْسَهُ لَغَنِيٌّ ‏”‏‏.‏ وَأَمَرَهُ أَنْ يَرْكَبَ‏.‏
The Prophet (ﷺ) saw an old man walking, supported by his two sons, and asked about him.
The people informed him that he had vowed to go on foot (to the Ka`ba).
He said, “God is not in need of this old man’s torturing himself,” and ordered him to ride.
[“Sahih Bukhari”, 1865].
https://sunnah.com/bukhari/28/45

Imam al-Shaatibi explained that deliberately seeking hardship is against the principles of religion, but being patient when hardship comes on you – is required & rewarded.

For example, there is reward in even a prick of a thorn, but there is no reward in deliberately throwing yourself into thorns to get reward.

The same applies to deliberately making Wudhu with cold water to increase the suffering, when warm water is available etc.

This is a flawed understanding of religion.