Likely a modern surname-style invention, probably modeled on English place and family names with no single established etymology.
Galvester is likely a modern surname-style invention, probably modeled on English place and family names rather than deriving from a single established etymology. That makes it feel constructed in the same broad way many modern rare names are: by borrowing the shape and authority of surnames.
The result is a name with a sturdy, almost formal sound. Galvester feels distinctive, slightly old-world, and a little unexpected, which gives it a memorable presence. Because it is so rare, it reads more like a deliberate creative choice than a inherited traditional name, and that adds to its individuality.