I even think this has been tried. The canister version is indeed unworkable, but changing the whole back part into a digital adapter was done multiple times.
One of issues I read somewhere is that distance between film-patrone to imaging area is not standardized, and also what I figured is digital sensors needs spaces to the back of focal plane which film cameras cannot accomodate. This is apparent just from comparing digital continuations of film camera brands.
See e.g. https://casualphotophile.com/2022/05/19/digi-swap-im-back-re...