A surviving Ukrainian frigate would still be trapped by Black Sea geography

If Ukraine's frigate had not been scuttled in March 2022, what could it realistically have done in the Black Sea?

Very little: its condition, weak air defence, confined operating area, Russian surveillance, and diplomatic constraints would make it an exposed target rather than a useful raider.

The frigate's condition and weak air defence offered little basis for an independent raiding mission. Dense surveillance and the confined Black Sea would make a conspicuous warship difficult to hide. Russian forces could concentrate against it once located. Passage through the Turkish straits was another possibility, subject to Turkey's decision. Supplying a belligerent warship could also create diplomatic difficulties for a neutral state.