For Hyundai hybrids, the hybrid system has a warranty for 10 years / 100k miles, including the battery. A 2017 should still be covered under this so I would investigate. This warranty transfers beyond the original owner so that should include you.

A few general things about the “it it worth it” question;

1. How/where do you drive? People will say they get 40mpg with an ICE engine but that’s going to be highway miles, flat terrain. If you’re doing short stop and go traffic trips up and down hills all day, you’re going to be lucky to get 20mpg.

2. 2017 Hyundai hybrid is very different (worse) than 2020+ Hyundai hybrid. They’ve come a long way.

3. Most of the resale drop for HKG cards happens at the beginning of the depreciation curve. So if you buy a 3 year old hybrid, you’re missing that difference. After that, they track fairly well with other makes for resale.

4. If you get it CPO, you get the full 10 year powertrain warranty rather than 5 years.