It seems inline IME display is possible even with the official build, but for now the following build is more comfortable to use. It supports W32-IME.
mhatta/emacs-26-x86_64-win-ime
Update: Starting with Emacs 27, W32-IME can also be used with GNU's official build.
[Emacs] Use Emacs 27 on Windows 10
I swap Caps and Ctrl with ChangeKey. It is old, but it still works. (There may already be a generation that does not know LZH.)
http://satoshi3.sakura.ne.jp/f_soft/dw_win.htm
I appreciate that an IME-enabled build is provided.
Swapping Caps and Ctrl is essential when I change PCs. Editing the Windows registry works too, but if ChangeKey still works, it is easier.
Test Environment
Windows 10 Pro version 1909 (OS build 18363.693)
64-bit GNU Emacs 26.3 for Windows (with IME patch) "GNU Emacs 26.3 (build 1, x86_64-w64-mingw32) of 2019-12-31"
ChangeKey v1.50