@Edna You said the batteries seem "fatter"... Are you 100% certain your Sony batteries are "authentic"? I only say that because the Sony VTC5 were probably the most counterfeited battery in the past couple of years Fatter batteries may or may not indicate a counterfeit, but to me it would be a reason to have doubt....
I have four (authentic) VTC4 left, and they are all still functioning near-new after 2.5 years (and over 300 charge cycles), which is actually better than a couple of my LG HE2's (which seem to lose charge pretty fast these days), despite them being only a year old and have gone through only 100-120 charge cycles. Even a couple of my Samsung 25R (blue) are starting to wear down in capacity, but they still hold out 3/4 to all day, and they're all 1.5-2 years old with well over 200 charge cycles each.
I've heard others say their RX 200, 200s, or 2/3 behave the same way (lasting only a day or less, even with 3 batteries), and others may get a couple days, but I suspect they are using a much higher resistance coil, or aren't chain-vaping it? High battery drain and the size/weight of it... along with always having to carry 3-6 extra batteries instead of 1-2... have been the reasons I've not bought one, lol. Then again, I'm perfectly happy vaping my 1.2 Ohm coils in a 50-75W single-battery mod... TC or Wattage-mode... I'm good either way