You need to find out if the problem is that your house needs lots of heat or your heat pump is running inefficiently. The way to do that is to get your COP figures (coefficient of performance) from the heat pump? Ideally you want separate COP figures for heating and hot water.
If your COP is high then the problem is that your house needs lots of heat. If it's low your heat pump is running inefficiently and you might be able to change some settings to improve it.
1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊