Being similarly frustrated with how complicated it is to set up, I've created an Ansible playbook to automate it all (and run all services in containers): https://github.com/spantaleev/matrix-docker-ansible-deploy

By default, it sets up Synapse and a bunch of other services around it that are necessary to really make it useful (Postgres instead of the default under-preforming SQLite; mxisd as the identity server; STUN/TURN server for WebRTC calls; riot-web; various bridges; etc)