There’s a meta thread for discussing the implementation of QWT : qubes-windows-tools: Support for Windows 10/11 · Issue #1861 · QubesOS/qubes-issues · GitHub . Qubes team member omeg is making significant contribution to the modern QWT and Windows-Qubes integration.
As far as I can tell, through GWeck’s report ( Windows 11 in Qubes - #169 by GWeck ) seamless mode used to work under Qubes 4.2.4 and Windows 10 with QWT 4.2.1, but not Windows 11.