[yrui]

I've been running OpenBSD more than 15 years, and it does have a learning curve.

One area to consider as a happy Debian desktop user is using OpenBSD as a router OS. PC Engines (I have no affiliation to them) makes a very nice router called "Alix" and OpenBSD works well on it. Previously, people were installing it on Soekris routers before they went out of business.

OpenBSD's firewall pf is by far my favorite, and it and OpenBSD have a lot of nice networking features and tools to tinker with. It's free of blobs (in the default install), free of known bugs (in the default install--but generally your router will work well with only the default install), and configured to be reasonably secure by default. The documentation is also frequently praised.

How many other modern, full-fledged, well-maintained and open code OSes run in 32 Mb of RAM?

[thijsvandien]

ALIX is EOL. Nowadays you'll want to use their APU (excellent too).