I might have just answered my own question from the CSA website for Matter 1.4:Any idea if they're adding hot water to Home at some point?
"Water Heaters – Electric water heaters can be set to a preset temperature or percentage, letting users monitor hot water levels. A boost command, which enables rapid heating from multiple energy sources for situations where hot water is needed quickly, allows temporary overrides in the heating schedule, ideal for situations like hosting guests. This gives consumers more control and flexibility. Additionally, the new Water Heater Mode cluster provides users with the ability to easily toggle scheduling on and off, making it simple to adjust heating patterns when normal routines change."
So I guess if it only got added with Matter 1.4 that's only been fixed in November, that's why I haven't got it yet, but it'll be coming sooner or later...