I bought one of those passively cooled router boxes from AliExpress and have been running opnsense for over a year on it now. It’s way overkill for router + ad blocking, but it’s been working great.

The only reason I want it on the router is if either my vm or my server go down for whatever reason I have no access. My router is way overkill hardware wise (it’s running opnsense and Adblocking and I’ve never seen above 2%) cpu usage.