Yes this works (see the post from awiouy in response earlier where he confirms) but as you correctly suppose, you cannot have Kodi active and the other distro active at the same time else both fight over the same hardware resources. This is also the case with the current Chrome addon for x86/64 (X11) where Kodi needs to be stopped while it's active - and it's one of several reasons why we regard the current "solution" as a bit of a hack and that something fully integrated into Kodi is real way forwards. However the exploratory work that's already been done in this area by Kodi developers has also shown that it's not a trivial capability to add, so while you are correct to be non-defeatist (it's not impossible and someone just has to do it) we're also correct to be realistic about the likelihood of it being done anytime soon (in the last 10-year period, nobody didi it).
Casting would also be nice and a solution for many users, but that also requires Kodi support and the developers are really not fans for proprietary crap (a lesson learned the hard way) so the reality of there being multiple "standards" for casing depending on macOS/Win/Linux/iOS/Android means it's also a reverse-engineering/bad-code and political issue. So native casing isn't likely to be a fruitful way forwards either.
So on this specific topic "get a chromecast" or dual-boot with Raspbian/Armbian/etc. are "sucky but sensible" options and IMHO chromecast would be the more practical to live with.