That is indeed correct. Porting Handheld support to 64-bit required basically re-writing that entire module since the tech it was based on was discontinued by Microsoft and as such not available in 64-bit.
This was a huge project, and because we don't want to go forward with two different Handheld modules, it'll also replace the Handheld module in 32-bit - but because it was such a huge change, we decided to hold off until MC24, so we don't introduce something potentially unstable and requiring a lot of testing still this late in the MC23 cycle, which may end up leaving it partially broken in the worst case.
Instead, MC24 will get it, which is going through a long testing and development phase to make it stable and reliable. A new version is always a better time for us to do "breaking" changes, as it gives us the time to work through all the kinks with internal and public testing, before its considered "stable".
Its unfortunate that MC23 64-bit still lacks a few features, but offering 64-bit in MC23 already was initially more of a test then anything else, but it worked pretty well that we accepted that some features may require additional work after it was released. The alternative would've been that we did all that work beforehand, and you may not have gotten 64-bit until MC24. But we usually prefer offering such things earlier, even if there are still known limitations.
As of MC24, 32-bit and 64-bit should have full feature parity, at least from our side. There are external components which are not always available in 64-bit, over which we have no influence.