Best way to get to Yufuin from Tokyo?

Hi,

I am looking at the options, and my research shows that basically it's either bus from OIT airport (which is located far from everything) or train/bus from Fukuoka.

1. OIT airport bus schedule does not align well with JAL arrivals. Might have to either spend a while at the airport after arriving or fly out of TYO uncomfortably early.
2. Fukuoka train/bus, but I am not sure what the schedule will be in March. It takes longer than OIT bus (2 vs 1 hr), but the schedule may align better with the flights. Also, I prefer trains over buses.
3. Rent a car: not sure I am comfortable doing it given the inverse traffic direction in Japan (and the added hassle of renting/returning a car). Is Japan free from unscrupulous rental practices (like claiming that an old scratch is new damage)?

I am strongly leaning towards train or bus (in that order).

Are there any options I am missing?

What would you take? Someone said that some buses are meh in that area. Is train a far better option?

Thanks!