Is there a way to force the temp sensor to use routers?

[JacekKac]

Some of temp sensor are constantly droping out of the network - low lqi. There are repeaters in place:

Tuya TS011F_plug_3
and
IKEA [E1746]

but they are not willing to connect to them instead choosing the coordinator which is fair away. In case of Temp_2 and Temp_3 they are 2 meters away from Tuya plug, and 4 meters away of IKEA. None of them are willing to join them.

[chris-1243]

What kind of sensor are you using (brands, etc...)

I would remove those two sensors from your network and factory reset them.
Now, select the router you wish to use then enable permit join. Then, start the pairing process