Lack of response to the last post suggests that fellow posters might consider this thread as deceased, perhaps with some justification. However, I still have the idea going round in my head, so a further attempt at “exorcism” might be worth a try.
Let's return to the wave/particle duality. My understanding is that QM is consistent with the idea that particles may not actually exist as physical entities. The more precisely one can locate a wave, the more it resembles a particle. This might lead to the conclusion that a particle is nothing more than a precisely located wave.
The next step is to consider that the wave, in its own frame of reference, is still an expanded wave, going to infinity and occupying the entire Universe. Only in the frame of reference of an observer might the wave be considered as a particle, having location and mass.
The idea that every wave occupies the entire Universe, and might continue to do so, even if an observer perceives it as being localised, may be counter-intuitive, but that certainly does not necessarily mean it cannot be the case. QM tells us that our reality is non-local, although this is not what we perceive. Instantaneous actions between entangled particles can (probably) occur over boundless distances. Something links these particles. Would it be totally illogical to suggest that they are linked by their wave nature, and that this wave nature is their normal and permanent state? If this were the case, it might be only our restricted 4D view of reality that obliges us to interpret their state as particulate under certain conditions. If this were the case, it would follow that their mass must be "supplied" by observation.