HN user
I find hyper quite nice to work with to build reverse proxies, mostly thanks to the HTTP client and server having common types for request, response, headers and body streams etc. I agree that it is only a decent lower level library rather than a full featured proxy framework though.
I use a mini PC as router too, running Ubuntu though. It works really well for me. I chose linux instead of pfSense because it is a lot more flexible, and I was already quite proficient in managing linux systems.
I often use make to run jobs in parallel. It is nice to be able to continue after an error or breakage, especially when working with large workloads.