is there no easy way to create a reference line at 2.7 and 4 in a chart like below without creating a input number, automation, and template sensor?
Input_number seems to be sufficient (with same UoM).
Or consider some custom card like apexcharts-card - it could support drawing graphs based on some “data generator” with no need to create entities.
Thanks @Ildar_Gabdullin
I ended up doing an input number , automation to generate history for stock hostograph, then I moved to the mini graph card