There is no difference in image quality between the two.
The improvements of kr compared to kx: viewfinder focus red dot indicator, display pixels are greatly improved, special focus light is added, processor is improved and continuous shooting, focusing speed and maximum sensitivity are slightly improved. The way to change the focus point has also changed and the skin has changed a bit. Lithium batteries can be used.
First of all, what battery are you using? If it's a row of disposable AA batteries bought on the street for a few dollars, I think you can save... KX is very picky about batteries, and the most compatible are usually the few disposable batteries at lithium supplied with the machine. Battery (it is said to play almost 2000 images, but I have never done this test personally. Anyway, I useusually rechargeable batteries, and the lithium battery has not been used many times so far). Then there is the Ailepu rechargeable battery from Sanyo. When paired with the original smart charger, it can last up to almost a thousand shots (provided you don't buy a fake product). With a silly charger it can last about 500 shots. . As for disposable AA batteries, they are only intended for emergency use, with a maximum of 300 sheets.
Then it's a problem with your settings. I don't know how you set battery recognition in the menu. Before the firmware upgrade, the kx's battery recognition was inaccurate. For example, the voltage of a rechargeable lithium battery is 1.5V. According to this standard, the rechargeable battery is considered dead as soon as it is installed (because the voltage of the rechargeable battery is 1.2V). The situation youwe describe is therefore very likely to occur.
It is recommended to first use a few disposable lithium batteries supplied with the machine and change the battery settings to lithium batteries to see if there is still a problem. Then use a rechargeable battery and change the battery settings to rechargeable battery (the penultimate item) to see if the problem persists. If it's still drawing a lot of power, there may be an internal short or something, and it needs to be sent in for repair.