Hi bro! Past 6 months ah 14 plus use panren nalla perform pannuchu but past 1 month ah whatsapp instagram YouTube mattum lagging issues iruku for example whatsapp la oru 400 msg iruka group ah open panna 10 sec lag aavuthu and moreover i maintaining my battery health in a decent manner cycle ah maintain panren but sudden ah 100 la irunthu 97 ku drop aayiduchu is it serious or normal coz ipo tha first time ios use panren so please get it clarified for me bro… 
hello bro, battery health sudden reduce could be due to our usage and refresh happened. explained here,
WhatsApp, Instagram app hanging problem ku iPhone la free storage evlo irukunu paarunga. once phone a restart pannitu check pannuga. and appstore la ella apps um updated a irukanum check pannunga. then iOS latest 16.5.1 version update agirukanu check pannunga.
Then check how it works bro. I am also using iPhone 14 Plus and so far its working good bro. above steps try pannitu oru one week use pannitu sollunga bro.