There is an influx db node that makes it really easy to use with node red, but there is some learning curve involved. I would go that way rather than sqlite though. I am sure there will be some sample flows in flows.nodered.org
With the sample rate it is best to set that based on what the control loop requires rather than on graphing requirements. You don’t want to compromise control in order to satisfy graphing requirements, there are other ways to do that such as limiting the sample rate going to the graph but keeping the control loop at whatever speed it needs. However, I see from the previous charts that the maximum slew rate (under cooling anyway) may only be about 1C/hour, and since the resolution of the sensor is 0.0625C that is one bit of resolution about every 4 minutes. You want the sample rate to be higher than this so one minute should be fine.
I am a bit confused by the megabyte every five seconds. I would have expected it only to transfer the latest data eac time, the chart buffering is done in the browser. That is assuming you are just feeding each sample into the chart. It sounds as if it is sending the complete chart every time which is odd.