Tomato WDS
The Tomato Linux distribution for MIPS and ARM routers is already able to do this.
The AP + WDS mode is used to slave the MAC addresses of the master and slave nodes.
https://learntomato.com/choose-wireless-bridge-mode-tomato-network/
https://en.wikibooks.org/wiki/Tomato_Firmware/Installation_and_Configuration
I'm a big fan of the Shibby Tomato Bandwidth Limiter feature - it's the easiest way that I know of to keep Windows 10 bandwidth usage under control. Runs well on an old, cheap WRT54G.