When should I replace the oil on my Audi SQ5 hybrid?

I drive a 2020 Audi SQ5 mild-hybrid. As I drive less than 5,000 miles per annum, I asked Audi to change my oil as it's a year old. They said it was unnecessary as the schedule is two years. Do you think...

Are PHEVs expensive to run and maintain?

I haven't seen any discussion on maintenance costs for PHEV. Presumably, it must be quite expensive since you are maintaining an EV plus an ICE?

Can I buy a hybrid even if I don't use it during the winter?

I am looking at a Toyota Yaris, the car will not be used in the winter months and garaged. Will this affect the life of the lithium batteries if not used for four months each year?

Do plug-in hybrids self-charge while driving?

Does a plug-in hybrid have any self-charging capability?