An alternative battery, but bigger and heavier, might be the RoyPow 6Ah. I’ve just bought the 12Ah version to use in my campervan. The 6Ah is 0.9Kg. The voltage under load when I tested it yesterday was around 12.7 to 12.5 when drawing 7A to power my IC-7300 at around 40W output power. Under a lower current it would be about 13 volts I think.
www.amazon.co.uk/RoyPow-Phosphate-Rechargeable-Replacement-Scooters/dp/B08S74VW95