As you can see here, theres a bug with signal strenght, distance between router and extenders is aprox 1 meter away one from another.
Router model: Archer AX73 V2.0 - Updated to latest firmware!

version 1.2.1 build 20250717 rel. 40826

Extender model: RE605x V3.0 - Updated to latest firmware also!
version 1.3.10 build 20250817 rel. 63070

Just to add, Signal strenght lights on the EXTENDER is Solid Blue which means the signal is perfect!