Just wanted to say that this short list was insanely helpful for a network noob like me. Thank you so so much.
Just one minor addition, the wireless can stress the CPU as well on heavy usage (IRQs keeping the CPU cores busy) - multi-core SoCs. (all of the ones I listed) provide a significant benefit towards the higher end of the performance spectrum.
I wouldn't be using OWRT as I setup Ubuntu to manage / build.
CLI only needs to be done once to configure a couple of things to get it to work and then you leave it alone. Other than system updates which can be done by GUI or CLI.
If you add a NIC for the AP then some additional configuration is needed to get it to come online when you reboot the system but nothing too difficult. If you want to be future proofed then WIFI 6 is gotten with an external AP and that's a web GUI.
Interesting! Where should I look for options for Ubuntu-based SQM and other helpful OWRT features? Is there a way to utilize opkg on Ubuntu?
There are multiple options for AQM / QOS as it's a full blown OS not specific to routing / switching. I don't personally worry about it since I'm not gaming online or doing buffer sensitive data.
https://manpages.ubuntu.com/manpages/impish/man8/tc-codel.8.html
https://www.bufferbloat.net/projects/cerowrt/wiki/Smart_Queue_Management/
https://github-wiki-see.page/m/gautamramk/FQ-PIE-for-Linux-Kernel/wiki/Active-Queue-Management
If you really need to prioritize things though it can also be done through iptables rules which are easier to manipulate for rate limiting / prioritizing traffic based on a host or subnet.
https://www.telogic.com.sg/Imagestream_Tech_QOS%20with%20iptables.html
SQM can also be installed on systemd based distributions like debian or ubuntu, see https://github.com/tohojo/sqm-scripts.
That said, for a networking beginner OpenWrt might be an easier starting point with its reduced scope and its GUIs for many network related things. For example OpenWrt's default firewall GUI beats Ubuntu's by a wide margin....
Please don't.... get yourself accustomed to OpenWrt before 'inflicting' it on your family, espicially if you are not available for on site maintenance work....
Cloning a configuration that works well on your own site is a different kettle of fish as it will allow you to test configurations locally before deplying them remotely....