Capacity is selected based on the energy you want to shift from production hours to consumption hours. It is not determined solely by the size of your home or the output of your panels.
We need to know how much surplus energy is available for charging and how many kWh you typically consume after sunset. We assess this across different seasons, because production and needs do not remain constant throughout the year.
Compare the usable capacity, meaning the energy you are allowed to use, and not just the nominal capacity. Also check the charging and discharging power, compatibility with the inverter, losses, and the percentage that will remain reserved for backup.
A larger battery does not guarantee greater savings: it must be possible to charge and use it regularly. If you want backup power during an outage, also note which appliances you want to power and for how many hours. This is a different goal from maximizing daily self-consumption.