1. Go with direct 1G Ethernet copper cabling wherever possible. It is infinitely more reliable, economical and has much higher bandwidth.
2. Do not “power line Ethernet” products. They do not work.
3. Buy off-lease enterprise grade Cisco switches, firewall and mesh wireless access points instead of TP-Link/assus/Trendnet or any other consumer brand. It will work better for much longer.
4. Use major name jacks and patch cables from Leviton or Belden or Hubbel and use brand-name Cat5E or Cat6 cable instead of cheap no-name low quality cable.