By definition, a metal is a material in which, at a temperature of 0 Kelvin, the density of states at the Fermi level is not zero. A degenerate semiconductor may not meet this criterion. Depending on the temperature, it can become non-degenerate. The metal remains degenerate throughout the temperature range of its existence.

A degenerate heavily doped semiconductor will show metallic characteristics at high temperature i.e, the decrease in electrical conductivity due to increased electron scattering.

However, at low temperatures if the Fermi level is not in the conduction band in a degenerate SC it will show usual SC behavior whereas the metal will remain metallic even at low temperature.

For Seebeck coefficient I would request you to refer to the discussion in link below:

I hope it helps.

https://www.researchgate.net/post/What_is_the_main_explanation_for_increased_thermopower_Seebeck_coefficient_with_rising_temperature

There exist a finite energy bandgap for degenerate semiconductors, which the free carriers overcome due to thermal excitation. But for metals the concept of bandgap is absent.