Turkish dua practices after the Tasleem of a fardh prayer – bidah?

At our masjid in Turkish Republic of Northern Cyprus: after every fard salah the Muadhin recites the prescribed dua loud in a distracting manner, then doing Dhikr/Adkhar loud in congregation. Thereafter, the imam recites a dua loud, then recites Al fatiha and everyone opens their hands and reads al fatiha.

Is there any authentic teachings about this or is it another cultural bidah?

Turkish people follow hanafi school of thought.