I assume you bought a pre finished floor. Get the same wood species unfinished, and match the stain on site. Better than a total change in flooring materials

Yep. Jan's on it. It is possible to "match" this floor with a high end (read: expensive) engineered hardwood that is UNFINISHED. Once installed it is SITE FINISHED (just like a solid hardwood) in a stain to match. This is one of the ways you will find a 'match'. This can be done. It won't be cheap but it can be done.

Or you look at a completely different floor and run it at an angle...or a different direction somehow...or you remove what has already been done and start over with a whole new floor.

3 options: 2 are expensive and one is cheaper with a problem with colour matching/plank matching, etc.

Personally I like option 2B...finger parquet stained to match the hardwood in the rest of the home. No need to "match" the planks, but you can get a colour match that works without having to go to all that trouble of finding unfinished engineered hardwood that is ready for site finishing.

BTW: that is one HECK of a step down....is there any plan to deal with the very different floor heights?