Entirely possible. Obviously Apple wouldn't have been interested in letting you upgrade the RAM even if it was doable.
I'd love to have more points of comparison available, but Strix Halo is the most analogous chip to an M-series chip on the market right now from a memory point of view, so it's hard to really know anything.
I very much hope CAMM2 or something else can be made to work with a Strix-like setup in the future, but I have my doubts.
