Must reduce threshold height difference, but how?

I have a threshold height difference issue in my kitchen. The house was built in the 1950’s & has asbestos tile under 1/4 inch plywood. I have removed 2 layers of vinyl that’s on the plywood but I can’t take up the plywood for obvious reasons. The problem is with just the plywood, the kitchen floor is about 1/4 inch higher than the hardwood floor that it transitions. With 1/4" Hardi board, mortar, & tile I think the height difference is too great. Any ideas to make the difference less? If it matters, I believe the bottom layer is concrete because that is what it was in the bathroom.

So what your saying, I think, is that your kitchen floor will actually be like 7/8 to 1" higher when finished. If so then can you make a longer(wider) transition piece to make a more gradual slope. You could use a hard wood like your floor. If you don’t have experience with table saws and other saws, you can have someone make you one. They might even have a better idea. You would have to figure out the height difference and figure out how thick of a board you will need. Then how much can you slope it. Will it work with a 8" or 10" wide board. How does it Finish into the wall, jamb, etc. just an idea. Good luck

Most flooring companies sell transitions threshold pieces, if not you can have one custom made to have a slow transition from height to the next.

In some situations you can remove the plywood substrate to achive proper heights but you will need to add additional blocking between the floor joist to support the threshold, House built before yours 20 years and better always sat on the joist rather the plywood, you just need to make sure the blocking is secure and will not come loose over time.