Support for it already seems to be there in wine, so rather than wait for 6.11 I think I'll just go ahead and apply the patches myself to 6.10-rc7 and see if it makes any difference to the one game I regularly play. If my computer blows up as a result I'll let y'all know.
(Result: None. The versions of wine I have probably need patching or at least configuring in order to use it. In the course of briefly considering trying to work out how to do that, I discovered that the expected improvements are not nearly as dramatic as were suggested compared to what's already most often done in proton (fsync). The main benefit for most of us will be better compatibility, not huge performance gains. Well at least my kernel is ready for it.)