I don’t see the problem. Let me show how the Telldus Live! systems historical graphs looks (I have been waiting for Telldus support to do a restore of my system that have been locked for over a month. 
).
Here is the temperature graph of a Fibaro smoke sensor that doesn’t report that often:
As you can see there is a small ring on the graph showing the point that the data “21,4°” was registered. This ring is only displayed when the pointer is near the data point. If I drag the pointer to the right there will be nothing displayed until it gets near the next point which is 14/8 23:50. The cursor jumps between registered data points which makes it very easy to see if a sensor is active or if it’s not reporting/registrering in the controller.
To compare with how Homey Insight display data, this is a Fibaro motion sensor that the battery died a few weeks ago:
There is no way to know if the sensor is working or if the value is just the same since if you sweep with the pointer there is no graphic difference. Of course, if a lux value haven’t changed in a few weeks you might start to suspect that something is wrong…but I’m using these extreme examples to show what I feel is a potential improvement for Insight.
About a function to chose historical period I can’t believe that the amount of data would be a problem. I’m not talking about storing data for years and the ability to show every single data point from say May 10:th 2018.
Again from Telldus Live!. This time an outdoor temp/hygro sensor first showing the default display. Note the date span:
Lets say I’d like to check what the outdoor temperature was at 15:00 on the 13:th (two days ago). For this I change the dates to 2021-08-13 and 2021-08-13 making it show only that day:
This gives much higher graph resolution than the Homey choice of “Last seven days” that is the only option available if I want to check sensordata older than 24h.
I’m no programmer but I know that virtually nothing is impossible in the digital world. The only hurdles are money, time and will. If there is a will you only need time and money to get it done.
Maybe I’m alone in wanting this for Insight and then there will be no will from Athoms side to develop it. But if many users agree with me maybe they will take a look at it. That’s why I posted this under “Ideas & Suggestions”.
