Hi Bassem, the map looks very promising and like you are on the right track. See the discussion here for some recommendations on how to assess pseudosymmetry in cryosparc.
At first glance, I would try symmetry expansion, followed by local refinement with a mask on the peripheral domain (or single protomer), followed by 3D classification without alignments/shifts in relion using a similar peripheral domain mask. Does 3DVA demonstrate large motions on the periphery and inform on where to place a mask and fulcrum for local refinement?