I just bought a new AX5400 (Archer AX73) router and RE315 Range extender.  Both support OneMesh.  My intent was to use the RE315 as a OneMesh wired repeater/access point.  I currently have an older Linksys main router at one end of the house, wired ethernet to a TP Link TL-WA801ND configured as a repeater in the garage at the other end of the house.  This covers my whole house and most of the yard with good signal.

I wanted to just upgrade the old Linksys with the AX73 and the 801ND with the RE315, but it is not clear how to configure the RE315. I hoped to have seamless transfer of devices between the wireless locations assuming the OneMesh would do that.  I don't get good enough wireless signal in the garage from the main router to make it a totally wireless repeater.  I have the ethernet connection, but one reference said the RE315 can't use it as a "backhaul" in a mesh arrangement.

Is my only choice to setup the RE315 as an AP and give the same network SSID's and passwords?  Any guidance appreciated.