Some people have had battery problems - a dealer should replace a bad battery under warranty.

I've had 3 Yaris hybrids and never had a problem as an occasional user.

If you're the worrying type, you could get a jump-starter such as this one:
https://www.amazon.co.uk/NOCO-GB20-UltraSafe-Lithium-Gasoline/dp/B015TKPT1A

Hi

When you say occasional user how often would you leave the car undriven?

Up to 3 weeks during the COVID pandemic, but fairly often for a week otherwise.

Thankyouo