How to sum daily update in cost

I have an energy export entity that gets updated daily with previous day exported amount in £.

The goal is to feed it into something like a utility meter with no cycle and add/sum each daily update. Day1 £3 + Day2 £1 + Day x £y

I have tried to feed it into a utility meter but with all the different combinations of options it doesn’t quite work as expected. It kind of works but with any reboot of HA or device reload it adds the latest amount over over again.
Also tried riemann left sum which also kind of works but for some reason if there is no daily update for even few days it still keep increasing the sum.

Any suggestions what else can I try like a template or maybe I’m doing something wrong?

Thanks in advance.