A bit on the expensive side but it is based on openwrt with a bit of custom software on top by Turris (which is a daughter company of czech domain registrar CZ.NIC)
I bought one, the hardware is a bit very old, poorly I got it a bit early (they are a bit late, the MOX already uses ARMv8 and they still dont have m.2) but it is AWESOME!
this thing is absolute geek material and the powerful hardware allows for way more features. Their openWRT is highly modified and extended, their updates are likely better, they have packages you can add etc.
Really really great.
Already got DNSSEC running, and will add a 2TB SSD for a nextcloud server.
Already started modding, as the mPCIe slots are similar to what my Thinkpas T430 has.
Yeah geek material is probably the best tag and category for Turris, and I feel you with that old hardware, wish I had the same thing with just a bit better/modern soc and more ram.
We are committed to providing long-term support for our devices for as long as the Linux kernel continues to support them. For instance, our initial router, Turris 1.X, which was a part of the Turris security research program launched in 2013, is still supported after a decade.
I guess it's something along "we will try to support your device for as long as humanly possible" ? My ~three years old omnia is still getting updates (just like a regular linux box would), actually seems I have one pending right now:)