Can / should you put a 28C tire on a rim with an ETRTO of 622 x 14 Setting aside the questions of frame and brake clearance for the moment, my question is whether or not I can install 28C tires on my rims which have an ETRTO of 622x14.  I currently have 23C tires on the bike, which is what the bike came with originally, but am thinking of moving to 25C or even 28C tires but am not sure if 28C is too wide for these rims.

And the next question is, even if it does fit on the rim will it create a safety or performance issue to put 28C's on these rims?

My goal is to move from my old school 23C's to something with less rolling resistance and that give a little more forgiving ride.  Just want to be sure I do it safely and wisely.
There's no issue with running a 28 on this width rim. In the decades of 23mm tires being the norm and virtually all road rims being 13-15mm internal width, many cyclists rode 28s since it's the widest size many such road bikes can take.

32 is also fine. 35 is about where issues with squirmy feel are perceptible.