[prydey]

Most modern cars, especially those with start/stop function, will have an on board bms (battery management system) as well as variable voltage alternator (commonly called smart alternator).

Rarely will they charge the battery until it's full. It's just the way the system has been designed.

I've replaced my Ford batteries with OEM for many years now. They are exide I believe (stickered as motorcraft) and very competitively priced in my experience.