I’m using a ~30 USD thin client with a 4 port networking card (~20 USD), just using plain nftables on Debian. It routes handles my network just fine (complex rule set with many subnets & rules, 250/100 Mbps connection). Also using codel/cake for traffic shaping, avoiding lousy ping times even when downloading/streaming et c.
I use two TP-Link EAP 245v3 (ancient by now, but I can still use all my WAN speed from all rooms) for WiFi. Works great.
If I would redo it I’d use VyOS, OpenWRT or maybe OPNSense, but still using x86 hardware due to cost/power usage/performance. And then newer ceiling access points.