https://wccftech.com/samsung-galaxy-s10-lite-3100mah-battery-capacity/

Samsung has not incorporated large batteries in the Galaxy S8 or Galaxy S9+; limiting them to 3,000mAh of rated capacity. The Korean giant has instead relied on different forms of component engineering to deliver those battery efficiency metrics and it appears the company will be using the same approach with the Galaxy S10 Lite.

The smaller member of the Galaxy S10 series was always going to be the cheaper model but with that price reduction comes a list of compromises too. If you want to experience better battery life, owning a device with a larger footprint will always be a good practice.