-List of openwrt compatible routers: https://openwrt.org/toh/start

-Example of a basic gigabit ethernet device with RouterOS (without wifi): https://mikrotik.com/product/RB750Gr3

-pfsense is a good option, but you will need specific hardware for it, several network interfaces, etc. If you value consumption, maybe this is not the best option to start with.

If you need something specific, put it in the comments and we will look for it ;)