My setup:

cable modem to internet.

Router 1: Archer AX11000 v1.0 1.2.3 Build 20210719 rel.14861(5553)  connected to cable modem, got external ip 192.168.0.x, it has internal lan ip 192.168.1.1

Router 2 (Archer AX6000 v1.0 1.2.4 Build 20210719 rel.12163(5553)) connected to router 1 via ethernet, has ip 192.168.1.100 via dhcp (has internal ip 192.168.2.1)

Router 3 ( Hardware Version:Archer A10 v1 00000000 Firmware Version:1.0.5 0.9.1 v1000.0 Build 200928 Rel.32191n(5553)  ) connected to router 1 via ethernet, has ip 192.168.1.101 via dhcp (has internal ip 192.168.3.1)

The reason I have this setup is, I have a lot of 2.4ghz smart devices (light switches etc), and it seems after certain number of items (at this time I have 26), it became very difficult to add new devices.  My esp8266 will connect forever.

So question 1.  how many 2.4ghz devices can be on a single tplink router at the same time?

question 2, I am unable to have devices from the top network (i.e. 192.168.1.x) connect to lower levels (192.168.2.x or 3.x), but I am able to connect from lower networks to higher networks.  How to setup static routing to allow higher network items to connect to lower ones?  My static routing

Dest               Mask                   Gateway            Type

Does not seems to work.

Thanks!