I suspect that there are thousands of stringtheories out and about since 1970.
All of them having more or less constraints.

But, if all of these stringtheories were to be guided by one constraint only.
The
constraint that when a normal electron of a hydrogen atom in ground state is
compressed or squeezed into a Nuclear Electron of the space of a Neutron.
That this difference of a NuclearElectron compared to a normal electron is the
difference of the neutrino restmass.

So, give us a particular Stringtheory with the constraints of a NuclearElectron

and it should predict the restmass of the neutrino. The conversion of space of
a
normal electron into the space of a neutrino so that the normal electron has
been transformed into a nuclear electron should give the value of the neutrino
restmass.

Archimedes Plutonium,
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies