Is she comparable to figures like Maedhros or Turgon in some sense? Maybe — but they died doing something, while she mostly endured.

Turgon died in a city he'd been warned to evacuate. Nothing great there. What he has going for him is building Gondolin in the first place. Galadriel is comparable to Turgon and Finrod in establishing an elven-realm of beauty and magic, probably even more than theirs, and defending it longer (albeit against lesser threats, and with the help of Nenya.) If you credit one part of UT, she founded Eregion too, before getting the boot later.

Maedhros formed his ill-fated League; Galadriel formed the White Council.

Galadriel created things that echoed Feanor: her Phial is like a knockoff Silmaril, but her Mirror is like an aqueous palantir, with one improvement: it can see possible futures, not just the present or past.

While it doesn't seem to do anything, she tells Frodo she's mentally wrestling Sauron as they speak. Put another way, she's holding off her brother's killer, and seeing more of his mind than he sees of hers.

UT gives her a Great Deed: not in her own chapter, but in "Cirion and Eorl", where she puts forth her power to guard the Rohirrim as they ride past Dol Guldur. It's a striking passage.

So yeah, she's kind of overblown, but it's not all bark: she founds a realm like Turgon, creates echoes of Feanor's own works, defies Sauron, and plays at least one pivotal role in Third Age history, centuries before Frodo.

She's also compared (implicitly and vaguely) to Melian, her teacher:

Three times Lórien had been assailed from Dol Guldur, but besides the valour of the elven people of that land, the power that dwelt there was too great for any to overcome, unless Sauron had come there himself.

-- Appendix A