GreyLord
Legend
3.5 you can often ad hoc it. You don't need to convert it in most cases.
The original Kingmaker AP volumes (6 in total) were released for Pathfinder 1e, which isn't really convertible to 5e. They also are hard to find and can be extremely expensive when you do. This Hardback was originally made for Pathfinder 2e which isn't compatible with 3.5 overall. It also is far more reasonably priced compared to the original AP volumes when you can find them. In addition, Kingmaker (or Abomination Vaults) are basically full on campaigns which can take you months, if not years, to complete.
Abomination Vaults was also originally made for Pathfinder 2e.
However, with the adaptations built into the actual volumes there, both can be run for 5e. In my opinion, though I'm not the biggest fan of their rules, Paizo currently is the king of Adventures and making them in general.