They both use plume delivery - just of different chemicals....

They both use plume delivery - just of different chemicals. Plume is about physical distribution in nasal cavity

here is the simplest article I could find mentioning all the factors in nasal delivery via plume
https://link.springer.com/article/10.1007/s40005-020-00482-z

Key difference in this article compared to products concerned is the theory that they are creating a barrier in nasal cavity and binding ( enveloping) virus in mucus as opposed to delivering a chemical being absorbed in nasal cavity delivering a medicine.

IMO Plume is about droplet distribution in nasal cavity- it is a known from many historical studies so chemists know approximately how and where a spray droplet is deposited in nasal cavity in a human.
The droplets composition can be anything nano, ethanol chemical with carrier etc etc and that composition may affect the nasal passage by thickening mucus when creating a barrier etc etc.
1 spray 2 spray 10 spray it is all bout dosage and coverage
Repeating sprays is all bout how long it is "active" and how quickly is is cleared by normal Mucus system naturally refreshing itself and if the sprays composition changes that speed of refresh .