What is the ruling on adopting Abu Hanifa’s view that blood invalidates ablution, and adopting Shafi‘i’s view after the prayer, relying on it, and not repeating the prayer?

Scholars have differed on the issue of an ordinary person's adherence to a specific madhhab (school of thought). The preponderant view is that it is not obligatory for him to do so, and he is permitted to move from one madhhab to another, unless his intention is manipulation or the pursuit of concessions (rukhas). Al-Qarafi mentioned three conditions for moving between madhahib: that he does not combine opinions in a way that contradicts ijma' (consensus), that he believes in the virtue of the one he imitates, and that he does not pursue the concessions of the madhahib. Accordingly, there is no harm in moving from the Hanafi madhhab to the Shafi'i in the aforementioned issue, unless the intention is manipulation and the pursuit of concessions.