Routing is pretty easy for most use cases... firewalling an Internet connection, on the other hand, is just about impossible (thanks TLS 1.3) without pretty serious overhead, 3rd party maintained live subscriptions, TLS interception, and a willingness to say "no" to a lot of the shenanigans that modern programs and devices try to pull.

I recommend the free home version of Sophos for the least painful way to do it. Buy a Palo Alto with a full subscription if you are really serious.