Seeking guidance on Multi-WAN hardware and firmware selection

unfortunately no such openwrt capable commercially available hardware exists especially under 200$
https://forum.openwrt.org/t/so-you-have-500mbps-1gbps-fiber-and-need-a-router-read-this-first/
you need to combine a wired only router for multi-wan needs (use ERPro-8 if you like it) and 1 or multiple AP (like 1 or all your current 3 devices if the're capable) for your wifi needs