If you are lucky enough to clear E4 hard early, but not so lucky to get Umikaze, you may find E4 hard is difficult to farm.
First you must not go north. Bring 2 DD to win S in a node with installation boss and 2 BB tank is not a good idea. Second is boss support expedition. Normal support is not required because all nodes are sub or yasen in southern route.
Other than 2 Kongou class BB, you can add another 3 CA(V) or 2CA(v)+1BB in your fleet, CA are better at yasen but BB deals better damage against installation boss. Last slot should be a CVL or CV. Please keep in mind that total number of BB and CV must not excess 5 or compass will send you to deadend.
For equipment, BB and CA are 2 red guns, scout and Type 3 Shell. BB with AP can deal good damage to boss with cutin in day battle. But Type 3 is better because a chuuha (orange hp) BB still able to kill boss in yasen. In order to reduce risk in yasen nodes, CA can consider yasen equipment such as Star Shell, Night scout and Searchlight. Searchlight should install on flagship only or it may backfire.
E4 boss AS+ is 147, you may check online calculator  for your best CVL setup. There are no air battle before boss and CVL with bomber can help you to chip some damage on sub, which reduce chance of losing in sub node.