Only a small part of the loss is disallowed - just the part attributable to the sale of the shares that you purchased on 12/19. The remaining loss can still be used to offset gains. The disallowed wash sale amount should be shown on the 1099-B entry for the 12/21 sale. How do you know that Fidelity did not make the wash sale adjustment?
Look at Form 8949 in the tax return that you filed. In the entry on Form 8949 for the 12/21/22 sale, the disallowed loss should appear in column (g) with code W in column (f). If it's there, everything is okay and you don't have to do anything. The loss shown in column (h) is the net loss that you are allowed to claim, after adjusting for the wash sale.
