Home Network Troubleshooting and Optimization

I'm looking for an experienced IT technician to troubleshoot and resolve ongoing issues with my home network and Windows PCs. Current Network Setup: ISP: iiNet NBN FTTP (850/90 Mbps, PPPoE). Router: Ubiquiti Cloud Gateway Max (UCG-Max). Switches: 2 × Ubiquiti Flex Mini 2.5G. Wi-Fi: Eero Pro 7 (Bridge Mode). CAT6 Ethernet cabling throughout the house. Two Windows PCs connected via Ethernet, including one with a Realtek 2.5Gb adapter. UCG-Max manages DHCP and IP reservations. Main Issues: Windows frequently reports duplicate IP addresses, even when UniFi shows only one device using the affected IP. PCs sometimes receive incorrect IP addresses despite DHCP reservations. Internet connectivity is not always available immediately after starting or waking the devices. Devices occasionally have a valid IP address but no internet access. Similar problems existed with my previous TP-Link equipment, which was replaced with UniFi hardware. What I Need: A comprehensive network assessment to identify and permanently resolve these issues, including: DHCP, IP conflicts and network configuration. Router, switches, Eero Bridge Mode and Ethernet cabling. Windows network settings and Realtek drivers. PPPoE, DNS and MTU configuration. Network optimisation for stable, low-latency gaming (iRacing), Discord and streaming. My goal is to have a reliable network where all devices receive their correct IP addresses and connect to the internet immediately, without manual intervention. I would prefer an on-site visit to identify the root cause and implement a permanent solution. Could you please confirm your availability in Perth, estimated cost?