Wiring 5 wires into one terminal end
You might consider a busbar- a copper or brass bar with a number of holes drilled along its length.  You’d typically terminate each wire with a ring or spade terminal and then secure each one with a screw.  You’ll want the same setup for positive and negative.  This does result in quite a lot of exposed ‘live’ metal so it’s wise to put the positive busbar (assuming you’re using negative ground) in a non-conducting box, and a fuse between the battery and the busbar.